1104 lines
29 KiB
NASM
1104 lines
29 KiB
NASM
; *** Consts ***
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; Number of rows in the argspec table
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ARGSPEC_TBL_CNT .equ 31
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; Number of rows in the primary instructions table
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INSTR_TBL_CNT .equ 142
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; size in bytes of each row in the primary instructions table
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INSTR_TBL_ROWSIZE .equ 6
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; Instruction IDs They correspond to the index of the table in instrNames
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I_ADC .equ 0x00
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I_ADD .equ 0x01
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I_AND .equ 0x02
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I_BIT .equ 0x03
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I_CALL .equ 0x04
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I_CCF .equ 0x05
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I_CP .equ 0x06
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I_CPD .equ 0x07
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I_CPDR .equ 0x08
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I_CPI .equ 0x09
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I_CPIR .equ 0x0a
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I_CPL .equ 0x0b
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I_DAA .equ 0x0c
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I_DEC .equ 0x0d
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I_DI .equ 0x0e
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I_DJNZ .equ 0x0f
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I_EI .equ 0x10
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I_EX .equ 0x11
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I_EXX .equ 0x12
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I_HALT .equ 0x13
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I_IM .equ 0x14
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I_IN .equ 0x15
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I_INC .equ 0x16
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I_IND .equ 0x17
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I_INDR .equ 0x18
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I_INI .equ 0x19
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I_INIR .equ 0x1a
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I_JP .equ 0x1b
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I_JR .equ 0x1c
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I_LD .equ 0x1d
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I_LDD .equ 0x1e
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I_LDDR .equ 0x1f
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I_LDI .equ 0x20
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I_LDIR .equ 0x21
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I_NEG .equ 0x22
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I_NOP .equ 0x23
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I_OR .equ 0x24
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I_OTDR .equ 0x25
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I_OTIR .equ 0x26
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I_OUT .equ 0x27
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I_POP .equ 0x28
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I_PUSH .equ 0x29
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I_RET .equ 0x2a
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I_RETI .equ 0x2b
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I_RETN .equ 0x2c
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I_RLA .equ 0x2d
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I_RLCA .equ 0x2e
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I_RRA .equ 0x2f
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I_RRCA .equ 0x30
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I_SBC .equ 0x31
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I_SCF .equ 0x32
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I_SUB .equ 0x33
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I_XOR .equ 0x34
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; Checks whether A is 'N' or 'M'
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checkNOrM:
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cp 'N'
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ret z
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cp 'M'
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ret
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; Checks whether A is 'n', 'm', 'x' or 'y'
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checknmxy:
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cp 'n'
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ret z
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cp 'm'
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ret z
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cp 'x'
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ret z
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cp 'y'
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ret
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; Reads string in (HL) and returns the corresponding ID (I_*) in A. Sets Z if
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; there's a match.
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getInstID:
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push bc
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push de
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ld b, I_XOR+1 ; I_XOR is the last
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ld c, 4
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ld de, instrNames
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call findStringInList
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pop de
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pop bc
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ret
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; Parse the string at (HL) and check if it starts with IX+, IY+, IX- or IY-.
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; Sets Z if yes, unset if no.
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parseIXY:
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push hl
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ld a, (hl)
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cp 'I'
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jr nz, .end ; Z already unset
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inc hl
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ld a, (hl)
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cp 'X'
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jr z, .match1
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cp 'Y'
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jr z, .match1
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jr .end ; Z already unset
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.match1:
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; Alright, we have IX or IY. Let's see if we have + or - next.
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inc hl
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ld a, (hl)
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cp '+'
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jr z, .end ; Z is already set
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cp '-'
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; The value of Z at this point is our final result
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.end:
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pop hl
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ret
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; find argspec for string at (HL). Returns matching argspec in A.
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; Return value 0xff holds a special meaning: arg is not empty, but doesn't match
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; any argspec (A == 0 means arg is empty). A return value of 0xff means an
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; error.
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;
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; If the parsed argument is a number constant, 'N' is returned and IX contains
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; the value of that constant.
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parseArg:
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call strlen
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cp 0
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ret z ; empty string? A already has our result: 0
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push bc
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push de
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push hl
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; We always initialize IX to zero so that non-numerical args end up with
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; a clean zero.
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ld ix, 0
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ld de, argspecTbl
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; DE now points the the "argspec char" part of the entry, but what
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; we're comparing in the loop is the string next to it. Let's offset
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; DE by one so that the loop goes through strings.
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inc de
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ld b, ARGSPEC_TBL_CNT
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.loop1:
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ld a, 4
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call strncmpI
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jr z, .found ; got it!
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ld a, 5
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call addDE
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djnz .loop1
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; We exhausted the argspecs. Let's see if we're inside parens.
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call enterParens
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jr z, .withParens
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; (HL) has no parens
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call parseExpr
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jr nz, .nomatch
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; We have a proper number in no parens. Number in IX.
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ld a, 'N'
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jr .end
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.withParens:
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ld c, 'M' ; C holds the argspec type until we reach
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; .numberInParens
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; We have parens. First, let's see if we have a (IX+d) type of arg.
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call parseIXY
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jr nz, .parseNumberInParens ; not I{X,Y}. just parse number.
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; We have IX+/IY+/IX-/IY-.
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; note: the "-" part isn't supported yet.
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inc hl ; (HL) now points to X or Y
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ld a, (hl)
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inc hl ; advance HL to the number part
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inc hl ; this is the number
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cp 'Y'
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jr nz, .notY
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ld c, 'y'
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jr .parseNumberInParens
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.notY:
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ld c, 'x'
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.parseNumberInParens:
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call parseExpr
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jr nz, .nomatch
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; We have a proper number in parens. Number in IX
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ld a, c ; M, x, or y
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jr .end
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.nomatch:
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; We get no match
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ld a, 0xff
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jr .end
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.found:
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; found the matching argspec row. Our result is one byte left of DE.
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dec de
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ld a, (de)
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.end:
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pop hl
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pop de
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pop bc
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ret
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; Returns, with Z, whether A is a groupId
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isGroupId:
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cp 0xc ; max group id + 1
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jr nc, .notgroup ; >= 0xc? not a group
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cp 0
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jr z, .notgroup ; 0? not supposed to happen. something's wrong.
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; A is a group. ensure Z is set
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cp a
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ret
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.notgroup:
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call unsetZ
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ret
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; Find argspec A in group id H.
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; Set Z according to whether we found the argspec
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; If found, the value in A is the argspec value in the group (its index).
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findInGroup:
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push bc
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push hl
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cp 0 ; is our arg empty? If yes, we have nothing to do
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jr z, .notfound
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push af
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ld a, h
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cp 0xa
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jr z, .specialGroupCC
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cp 0xb
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jr z, .specialGroupABCDEHL
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jr nc, .notfound ; > 0xb? not a group
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pop af
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; regular group
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push de
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ld de, argGrpTbl
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; group ids start at 1. decrease it, then multiply by 4 to have a
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; proper offset in argGrpTbl
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dec h
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push af
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ld a, h
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rla
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rla
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call addDE ; At this point, DE points to our group
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pop af
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ex hl, de ; And now, HL points to the group
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pop de
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ld bc, 4
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jr .find
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.specialGroupCC:
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ld hl, argGrpCC
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jr .specialGroupEnd
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.specialGroupABCDEHL:
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ld hl, argGrpABCDEHL
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.specialGroupEnd:
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pop af ; from the push af just before the special group check
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ld bc, 8
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.find:
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; This part is common to regular and special group. We expect HL to
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; point to the group and BC to contain its length.
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push bc ; save the start value loop index so we can sub
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.loop:
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cpi
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jr z, .found
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jp po, .notfound
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jr .loop
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.found:
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; we found our result! Now, what we want to put in A is the index of
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; the found argspec.
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pop hl ; we pop from the "push bc" above. L is now 4 or 8
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ld a, l
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sub c
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dec a ; cpi DECs BC even when there's a match, so C == the
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; number of iterations we've made. But our index is
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; zero-based (1 iteration == 0 index).
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cp a ; ensure Z is set
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jr .end
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.notfound:
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pop bc ; from the push bc in .find
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call unsetZ
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.end:
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pop hl
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pop bc
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ret
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; Compare argspec from instruction table in A with argument in (HL).
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; For constant args, it's easy: if A == (HL), it's a success.
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; If it's not this, then we check if it's a numerical arg.
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; If A is a group ID, we do something else: we check that (HL) exists in the
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; groupspec (argGrpTbl). Moreover, we go and write the group's "value" (index)
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; in (HL+1). This will save us significant processing later in getUpcode.
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; Set Z according to whether we match or not.
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matchArg:
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cp a, (hl)
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ret z
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; not an exact match. Before we continue: is A zero? Because if it is,
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; we have to stop right here: no match possible.
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cp 0
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jr nz, .checkIfNumber ; not a zero, we can continue
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; zero, stop here
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call unsetZ
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ret
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.checkIfNumber:
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; not an exact match, let's check for numerical constants.
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call upcase
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call checkNOrM
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jr z, .expectsNumber
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jr .notNumber
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.expectsNumber:
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; Our argument is a number N or M. Never a lower-case version. At this
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; point in the processing, we don't care about whether N or M is upper,
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; we do truncation tests later. So, let's just perform the same == test
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; but in a case-insensitive way instead
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cp a, (hl)
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ret ; whether we match or not, the result of Z is
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; the good one.
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.notNumber:
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; A bit of a delicate situation here: we want A to go in H but also
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; (HL) to go in A. If not careful, we overwrite each other. EXX is
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; necessary to avoid invoving other registers.
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push hl
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exx
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ld h, a
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push hl
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exx
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ld a, (hl)
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pop hl
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call findInGroup
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pop hl
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ret nz
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; we found our group? let's write down its "value" in (HL+1). We hold
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; this value in A at the moment.
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inc hl
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ld (hl), a
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dec hl
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ret
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; Compare primary row at (DE) with ID in A. Sets Z flag if there's a match.
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matchPrimaryRow:
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push hl
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push ix
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ld ixh, d
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ld ixl, e
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cp (ix)
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jr nz, .end
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; name matches, let's see the rest
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ld hl, curArg1
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ld a, (ix+1)
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call matchArg
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jr nz, .end
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ld hl, curArg2
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ld a, (ix+2)
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call matchArg
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.end:
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pop ix
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pop hl
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ret
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; *** Special opcodes ***
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; The special upcode handling routines below all have the same signature.
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; Instruction row is at IX and we're expected to perform the same task as
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; getUpcode. The number of bytes, however, must go in C instead of A
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; No need to preserve HL, DE, BC and IX: it's handled by getUpcode already.
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; Handle like a regular "JP (IX+d)" except that we refuse any displacement: if
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; a displacement is specified, we error out.
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handleJPIX:
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ld a, 0xdd
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jr handleJPIXY
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handleJPIY:
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ld a, 0xfd
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handleJPIXY:
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ld (instrUpcode), a
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ld a, (curArg1+1)
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cp 0 ; numerical argument *must* be zero
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jr nz, .error
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; ok, we're good
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ld a, 0xe9 ; second upcode
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ld (instrUpcode+1), a
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ld c, 2
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ret
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.error:
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ld c, 0
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ret
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; Handle the first argument of BIT. Sets Z if first argument is valid, unset it
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; if there's an error.
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handleBIT:
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ld a, (curArg1+1)
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cp 8
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jr nc, .error ; >= 8? error
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; We're good
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cp a ; ensure Z
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ret
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.error:
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ld c, 0
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call unsetZ
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ret
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handleBITHL:
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call handleBIT
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ret nz ; error
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ld a, 0xcb ; first upcode
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ld (instrUpcode), a
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ld a, (curArg1+1) ; 0-7
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ld b, 3 ; displacement
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call rlaX
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or 0b01000110 ; 2nd upcode
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ld (instrUpcode+1), a
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ld c, 2
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ret
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handleBITIX:
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ld a, 0xdd
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jr handleBITIXY
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handleBITIY:
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ld a, 0xfd
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handleBITIXY:
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ld (instrUpcode), a ; first upcode
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call handleBIT
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ret nz ; error
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ld a, 0xcb ; 2nd upcode
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ld (instrUpcode+1), a
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ld a, (curArg2+1) ; IXY displacement
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ld (instrUpcode+2), a
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ld a, (curArg1+1) ; 0-7
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ld b, 3 ; displacement
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call rlaX
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or 0b01000110 ; 4th upcode
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ld (instrUpcode+3), a
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ld c, 4
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ret
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handleBITR:
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call handleBIT
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ret nz ; error
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; get group value
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ld a, (curArg2+1) ; group value
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ld c, a
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; write first upcode
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ld a, 0xcb ; first upcode
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ld (instrUpcode), a
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; get bit value
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ld a, (curArg1+1) ; 0-7
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ld b, 3 ; displacement
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call rlaX
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; Now we have group value in stack, bit value in A (properly shifted)
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; and we want to OR them together
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or c ; Now we have our ORed value
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or 0b01000000 ; and with the constant value for that byte...
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; we're good!
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ld (instrUpcode+1), a
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ld c, 2
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ret
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handleIM:
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ld a, (curArg1+1)
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cp 0
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jr z, .im0
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cp 1
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jr z, .im1
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cp 2
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jr z, .im2
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; error
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ld c, 0
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ret
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.im0:
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ld a, 0x46
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jr .proceed
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.im1:
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ld a, 0x56
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jr .proceed
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.im2:
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ld a, 0x5e
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.proceed:
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ld (instrUpcode+1), a
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ld a, 0xed
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ld (instrUpcode), a
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ld c, 2
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ret
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handleLDIXn:
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ld a, 0xdd
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jr handleLDIXYn
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handleLDIYn:
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ld a, 0xfd
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handleLDIXYn:
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ld (instrUpcode), a
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ld a, 0x36 ; second upcode
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ld (instrUpcode+1), a
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ld a, (curArg1+1) ; IXY displacement
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ld (instrUpcode+2), a
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ld a, (curArg2+1) ; N
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ld (instrUpcode+3), a
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ld c, 4
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ret
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handleLDIXr:
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ld a, 0xdd
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jr handleLDIXYr
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handleLDIYr:
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ld a, 0xfd
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handleLDIXYr:
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ld (instrUpcode), a
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ld a, (curArg2+1) ; group value
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or 0b01110000 ; second upcode
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ld (instrUpcode+1), a
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ld a, (curArg1+1) ; IXY displacement
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ld (instrUpcode+2), a
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ld c, 3
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ret
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handleLDrr:
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; first argument is displaced by 3 bits, second argument is not
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; displaced and we or that with a leading 0b01000000
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ld a, (curArg1+1) ; group value
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rla
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rla
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rla
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ld c, a ; store it
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ld a, (curArg2+1) ; other group value
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or c
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or 0b01000000
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ld (instrUpcode), a
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ld c, 1
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ret
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|
|
; Compute the upcode for argspec row at (DE) and arguments in curArg{1,2} and
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; writes the resulting upcode in instrUpcode. A is the number if bytes written
|
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; to instrUpcode (can be zero if something went wrong).
|
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getUpcode:
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push ix
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push de
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|
push hl
|
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push bc
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|
; First, let's go in IX mode. It's easier to deal with offsets here.
|
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ld ixh, d
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ld ixl, e
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|
|
; Are we a "special instruction"?
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bit 5, (ix+3)
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jr z, .normalInstr ; not set: normal instruction
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; We are a special instruction. Fetch handler (little endian, remember).
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|
ld l, (ix+4)
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ld h, (ix+5)
|
|
call callHL
|
|
; We have our result written in instrUpcode and C is set.
|
|
jp .end
|
|
|
|
.normalInstr:
|
|
; we begin by writing our "base upcode", which can be one or two bytes
|
|
ld a, (ix+4) ; first upcode
|
|
ld (instrUpcode), a
|
|
ld de, instrUpcode ; from this point, DE points to "where we are"
|
|
; in terms of upcode writing.
|
|
inc de ; make DE point to where we should write next.
|
|
ld a, (ix+5) ; second upcode
|
|
cp 0 ; do we have a second upcode?
|
|
jr z, .onlyOneUpcode
|
|
; we have two upcodes
|
|
ld (de), a
|
|
inc de
|
|
.onlyOneUpcode:
|
|
; now, let's see if we're dealing with a group here
|
|
ld a, (ix+1) ; first argspec
|
|
call isGroupId
|
|
jr z, .firstArgIsGroup
|
|
; First arg not a group. Maybe second is?
|
|
ld a, (ix+2) ; 2nd argspec
|
|
call isGroupId
|
|
jr nz, .writeExtraBytes ; not a group? nothing to do. go to
|
|
; next step: write extra bytes
|
|
; Second arg is group
|
|
ld hl, curArg2
|
|
jr .isGroup
|
|
.firstArgIsGroup:
|
|
ld hl, curArg1
|
|
.isGroup:
|
|
; A is a group, good, now let's get its value. HL is pointing to
|
|
; the argument. Our group value is at (HL+1).
|
|
inc hl
|
|
ld a, (hl)
|
|
; Now, we have our arg "group value" in A. Were going to need to
|
|
; displace it left by the number of steps specified in the table.
|
|
push af
|
|
ld a, (ix+3) ; displacement bit
|
|
and a, 0xf ; we only use the lower nibble.
|
|
ld b, a
|
|
pop af
|
|
call rlaX
|
|
|
|
; At this point, we have a properly displaced value in A. We'll want
|
|
; to OR it with the opcode.
|
|
; However, we first have to verify whether this ORing takes place on
|
|
; the second upcode or the first.
|
|
bit 6, (ix+3)
|
|
jr z, .firstUpcode ; not set: first upcode
|
|
or (ix+5) ; second upcode
|
|
ld (instrUpcode+1), a
|
|
jr .writeExtraBytes
|
|
.firstUpcode:
|
|
or (ix+4) ; first upcode
|
|
ld (instrUpcode), a
|
|
jr .writeExtraBytes
|
|
.writeExtraBytes:
|
|
; Good, we are probably finished here for many primary opcodes. However,
|
|
; some primary opcodes take 8 or 16 bit constants as an argument and
|
|
; if that's the case here, we need to write it too.
|
|
; We still have our instruction row in IX and we have DE pointing to
|
|
; where we should write next (which could be the second or the third
|
|
; byte of instrUpcode).
|
|
ld a, (ix+1) ; first argspec
|
|
ld hl, curArg1
|
|
call checkNOrM
|
|
jr z, .withWord
|
|
call checknmxy
|
|
jr z, .withByte
|
|
ld a, (ix+2) ; second argspec
|
|
ld hl, curArg2
|
|
call checkNOrM
|
|
jr z, .withWord
|
|
call checknmxy
|
|
jr z, .withByte
|
|
; nope, no number, alright, we're finished here
|
|
ld c, 1
|
|
jr .computeBytesWritten
|
|
.withByte:
|
|
inc hl
|
|
; HL points to our number (LSB), with (HL+1) being our MSB which should
|
|
; normally by zero. However, if our instruction is jr or djnz, that
|
|
; number is actually a 2-bytes address that has to be relative to PC,
|
|
; so it's a special case. Let's check for this special case.
|
|
bit 7, (ix+3)
|
|
jr z, .absoluteValue ; bit not set? regular byte value,
|
|
; Our argument is a relative address ("e" type in djnz and jr). We have
|
|
; to subtract (IO_PC) from it.
|
|
|
|
; First, check whether we're on first pass. If we are, skip processing
|
|
; below because not having real symbol value makes relative address
|
|
; verification falsely fail.
|
|
ld c, 2 ; this is a two bytes instruction
|
|
call zasmIsFirstPass
|
|
jr z, .computeBytesWritten
|
|
|
|
; We're on second pass
|
|
push de ; Don't let go of this, that's our dest
|
|
ld de, (IO_PC)
|
|
call intoHL
|
|
dec hl ; what we write is "e-2"
|
|
dec hl
|
|
call subDEFromHL
|
|
pop de ; Still have it? good
|
|
; HL contains our number and we'll check its bounds. If It's negative,
|
|
; H is going to be 0xff and L has to be >= 0x80. If it's positive,
|
|
; H is going to be 0 and L has to be < 0x80.
|
|
ld a, l
|
|
cp 0x80
|
|
jr c, .skipHInc ; a < 0x80, H is expected to be 0
|
|
; A being >= 0x80 is only valid in cases where HL is negative and
|
|
; within bounds. This only happens is H == 0xff. Let's increase it to 0.
|
|
inc h
|
|
.skipHInc:
|
|
; Let's write our value now even though we haven't checked our bounds
|
|
; yet. This way, we don't have to store A somewhere else.
|
|
ld (de), a
|
|
ld a, h
|
|
or a ; cp 0
|
|
jr nz, .numberTruncated ; if A is anything but zero, we're out
|
|
; of bounds.
|
|
jr .computeBytesWritten
|
|
|
|
.absoluteValue:
|
|
; verify that the MSB in argument is zero
|
|
inc hl ; MSB is 2nd byte
|
|
ld a, (hl)
|
|
dec hl ; HL now points to LSB
|
|
or a ; cp 0
|
|
jr nz, .numberTruncated
|
|
ldi
|
|
ld c, 2
|
|
jr .computeBytesWritten
|
|
|
|
.withWord:
|
|
inc hl ; HL now points to LSB
|
|
; Clear to proceed. HL already points to our number
|
|
ldi ; LSB written, we point to MSB now
|
|
ldi ; MSB written
|
|
ld c, 3
|
|
jr .computeBytesWritten
|
|
.computeBytesWritten:
|
|
; At this point, everything that we needed to write in instrUpcode is
|
|
; written an C is 1 if we have no extra byte, 2 if we have an extra
|
|
; byte and 3 if we have an extra word. What we need to do here is check
|
|
; if ix+5 is non-zero and increase C if it is.
|
|
ld a, (ix+5)
|
|
cp 0
|
|
jr z, .end ; no second upcode? nothing to do.
|
|
; We have 2 base upcodes
|
|
inc c
|
|
jr .end
|
|
.numberTruncated:
|
|
; problem: not zero, so value is truncated. error
|
|
ld c, 0
|
|
.end:
|
|
ld a, c
|
|
pop bc
|
|
pop hl
|
|
pop de
|
|
pop ix
|
|
ret
|
|
|
|
; Parse argument in (HL) and place it in (DE)
|
|
; Sets Z on success, reset on error.
|
|
processArg:
|
|
call parseArg
|
|
cp 0xff
|
|
jr z, .error
|
|
ld (de), a
|
|
; When A is a number, IX is set with the value of that number. Because
|
|
; We don't use the space allocated to store those numbers in any other
|
|
; occasion, we store IX there unconditonally, LSB first.
|
|
inc de
|
|
ld a, ixl
|
|
ld (de), a
|
|
inc de
|
|
ld a, ixh
|
|
ld (de), a
|
|
cp a ; ensure Z is set
|
|
ret
|
|
.error:
|
|
call unsetZ
|
|
ret
|
|
|
|
; Parse instruction specified in A (I_* const) with args in I/O and write
|
|
; resulting opcode(s) in I/O.
|
|
; Sets Z on success.
|
|
parseInstruction:
|
|
push bc
|
|
push hl
|
|
push de
|
|
; A is reused in matchPrimaryRow but that register is way too changing.
|
|
; Let's keep a copy in a more cosy register.
|
|
ld c, a
|
|
xor a
|
|
ld (curArg1), a
|
|
ld (curArg2), a
|
|
call readWord
|
|
jr nz, .nomorearg
|
|
ld de, curArg1
|
|
call processArg
|
|
jr nz, .error
|
|
call readComma
|
|
jr nz, .nomorearg
|
|
call readWord
|
|
jr nz, .error
|
|
ld de, curArg2
|
|
call processArg
|
|
jr nz, .error
|
|
.nomorearg:
|
|
; Parsing done, no error, let's move forward to instr row matching!
|
|
ld de, instrTBl
|
|
ld b, INSTR_TBL_CNT
|
|
.loop:
|
|
ld a, c ; recall A param
|
|
call matchPrimaryRow
|
|
jr z, .match
|
|
ld a, INSTR_TBL_ROWSIZE
|
|
call addDE
|
|
djnz .loop
|
|
; no match
|
|
xor a
|
|
jr .end
|
|
.match:
|
|
; We have our matching instruction row. We're getting pretty near our
|
|
; goal here!
|
|
call getUpcode
|
|
or a ; is zero?
|
|
jr z, .error
|
|
ld b, a ; save output byte count
|
|
ld hl, instrUpcode
|
|
.loopWrite:
|
|
ld a, (hl)
|
|
call ioPutC
|
|
inc hl
|
|
djnz .loopWrite
|
|
cp a ; ensure Z
|
|
jr .end
|
|
.error:
|
|
call unsetZ
|
|
.end:
|
|
pop de
|
|
pop hl
|
|
pop bc
|
|
ret
|
|
|
|
|
|
; In instruction metadata below, argument types arge indicated with a single
|
|
; char mnemonic that is called "argspec". This is the table of correspondance.
|
|
; Single letters are represented by themselves, so we don't need as much
|
|
; metadata.
|
|
; Special meaning:
|
|
; 0 : no arg
|
|
; 1-10 : group id (see Groups section)
|
|
; 0xff: error
|
|
|
|
; Format: 1 byte argspec + 4 chars string
|
|
argspecTbl:
|
|
.db 'A', "A", 0, 0, 0
|
|
.db 'B', "B", 0, 0, 0
|
|
.db 'C', "C", 0, 0, 0
|
|
.db 'k', "(C)", 0
|
|
.db 'D', "D", 0, 0, 0
|
|
.db 'E', "E", 0, 0, 0
|
|
.db 'H', "H", 0, 0, 0
|
|
.db 'L', "L", 0, 0, 0
|
|
.db 'I', "I", 0, 0, 0
|
|
.db 'R', "R", 0, 0, 0
|
|
.db 'h', "HL", 0, 0
|
|
.db 'l', "(HL)"
|
|
.db 'd', "DE", 0, 0
|
|
.db 'e', "(DE)"
|
|
.db 'b', "BC", 0, 0
|
|
.db 'c', "(BC)"
|
|
.db 'a', "AF", 0, 0
|
|
.db 'f', "AF'", 0
|
|
.db 'X', "IX", 0, 0
|
|
.db 'Y', "IY", 0, 0
|
|
.db 'x', "(IX)" ; always come with displacement
|
|
.db 'y', "(IY)" ; with JP
|
|
.db 's', "SP", 0, 0
|
|
.db 'p', "(SP)"
|
|
; we also need argspecs for the condition flags
|
|
.db 'Z', "Z", 0, 0, 0
|
|
.db 'z', "NZ", 0, 0
|
|
; C is in conflict with the C register. The situation is ambiguous, but
|
|
; doesn't cause actual problems.
|
|
.db '=', "NC", 0, 0
|
|
.db '+', "P", 0, 0, 0
|
|
.db '-', "M", 0, 0, 0
|
|
.db '1', "PO", 0, 0
|
|
.db '2', "PE", 0, 0
|
|
|
|
; argspecs not in the list:
|
|
; n -> N
|
|
; N -> NN
|
|
; m -> (N) (running out of mnemonics. 'm' for 'memory pointer')
|
|
; M -> (NN)
|
|
|
|
; Groups
|
|
; Groups are specified by strings of argspecs. To facilitate jumping to them,
|
|
; we have a fixed-sized table. Because most of them are 2 or 4 bytes long, we
|
|
; have a table that is 4 in size to minimize consumed space. We treat the two
|
|
; groups that take 8 bytes in a special way.
|
|
;
|
|
; The table below is in order, starting with group 0x01
|
|
argGrpTbl:
|
|
.db "bdha" ; 0x01
|
|
.db "ZzC=" ; 0x02
|
|
.db "bdhs" ; 0x03
|
|
.db "bdXs" ; 0x04
|
|
.db "bdYs" ; 0x05
|
|
|
|
argGrpCC:
|
|
.db "zZ=C12+-" ; 0xa
|
|
argGrpABCDEHL:
|
|
.db "BCDEHL_A" ; 0xb
|
|
|
|
; Each row is 4 bytes wide, fill with zeroes
|
|
instrNames:
|
|
.db "ADC", 0
|
|
.db "ADD", 0
|
|
.db "AND", 0
|
|
.db "BIT", 0
|
|
.db "CALL"
|
|
.db "CCF", 0
|
|
.db "CP",0,0
|
|
.db "CPD", 0
|
|
.db "CPDR"
|
|
.db "CPI", 0
|
|
.db "CPIR"
|
|
.db "CPL", 0
|
|
.db "DAA", 0
|
|
.db "DEC", 0
|
|
.db "DI",0,0
|
|
.db "DJNZ"
|
|
.db "EI",0,0
|
|
.db "EX",0,0
|
|
.db "EXX", 0
|
|
.db "HALT"
|
|
.db "IM",0,0
|
|
.db "IN",0,0
|
|
.db "INC", 0
|
|
.db "IND", 0
|
|
.db "INDR"
|
|
.db "INI", 0
|
|
.db "INIR"
|
|
.db "JP",0,0
|
|
.db "JR",0,0
|
|
.db "LD",0,0
|
|
.db "LDD", 0
|
|
.db "LDDR"
|
|
.db "LDI", 0
|
|
.db "LDIR"
|
|
.db "NEG", 0
|
|
.db "NOP", 0
|
|
.db "OR",0,0
|
|
.db "OTDR"
|
|
.db "OTIR"
|
|
.db "OUT", 0
|
|
.db "POP", 0
|
|
.db "PUSH"
|
|
.db "RET", 0
|
|
.db "RETI"
|
|
.db "RETN"
|
|
.db "RLA", 0
|
|
.db "RLCA"
|
|
.db "RRA", 0
|
|
.db "RRCA"
|
|
.db "SBC", 0
|
|
.db "SCF", 0
|
|
.db "SUB", 0
|
|
.db "XOR", 0
|
|
|
|
; This is a list of all supported instructions. Each row represent a combination
|
|
; of instr/argspecs (which means more than one row per instr). Format:
|
|
;
|
|
; 1 byte for the instruction ID
|
|
; 1 byte for arg constant
|
|
; 1 byte for 2nd arg constant
|
|
; 1 byte displacement for group arguments + flags
|
|
; 2 bytes for upcode (2nd byte is zero if instr is one byte)
|
|
;
|
|
; An "arg constant" is a char corresponding to either a row in argspecTbl or
|
|
; a group index in argGrpTbl (values < 0x10 are considered group indexes).
|
|
;
|
|
; The displacement bit is split in 2 nibbles: lower nibble is the displacement
|
|
; value, upper nibble is for flags:
|
|
;
|
|
; Bit 7: indicates that the numerical argument is of the 'e' type and has to be
|
|
; decreased by 2 (djnz, jr).
|
|
; Bit 6: it indicates that the group argument's value is to be placed on the
|
|
; second upcode rather than the first.
|
|
; Bit 5: Indicates that this row is handled very specially: the next two bytes
|
|
; aren't upcode bytes, but a routine address to call to handle this case with
|
|
; custom code.
|
|
|
|
instrTBl:
|
|
.db I_ADC, 'A', 'l', 0, 0x8e , 0 ; ADC A, (HL)
|
|
.db I_ADC, 'A', 0xb, 0, 0b10001000 , 0 ; ADC A, r
|
|
.db I_ADC, 'A', 'n', 0, 0xce , 0 ; ADC A, n
|
|
.db I_ADC, 'h', 0x3, 0x44, 0xed, 0b01001010 ; ADC HL, ss
|
|
.db I_ADD, 'A', 'l', 0, 0x86 , 0 ; ADD A, (HL)
|
|
.db I_ADD, 'A', 0xb, 0, 0b10000000 , 0 ; ADD A, r
|
|
.db I_ADD, 'A', 'n', 0, 0xc6 , 0 ; ADD A, n
|
|
.db I_ADD, 'h', 0x3, 4, 0b00001001 , 0 ; ADD HL, ss
|
|
.db I_ADD, 'X', 0x4, 0x44, 0xdd, 0b00001001 ; ADD IX, pp
|
|
.db I_ADD, 'Y', 0x5, 0x44, 0xfd, 0b00001001 ; ADD IY, rr
|
|
.db I_ADD, 'A', 'x', 0, 0xdd, 0x86 ; ADD A, (IX+d)
|
|
.db I_ADD, 'A', 'y', 0, 0xfd, 0x86 ; ADD A, (IY+d)
|
|
.db I_AND, 'l', 0, 0, 0xa6 , 0 ; AND (HL)
|
|
.db I_AND, 0xb, 0, 0, 0b10100000 , 0 ; AND r
|
|
.db I_AND, 'n', 0, 0, 0xe6 , 0 ; AND n
|
|
.db I_AND, 'x', 0, 0, 0xdd, 0xa6 ; AND (IX+d)
|
|
.db I_AND, 'y', 0, 0, 0xfd, 0xa6 ; AND (IY+d)
|
|
.db I_BIT, 'n', 'l', 0x20 \ .dw handleBITHL ; BIT b, (HL)
|
|
.db I_BIT, 'n', 'x', 0x20 \ .dw handleBITIX ; BIT b, (IX+d)
|
|
.db I_BIT, 'n', 'y', 0x20 \ .dw handleBITIY ; BIT b, (IY+d)
|
|
.db I_BIT, 'n', 0xb, 0x20 \ .dw handleBITR ; BIT b, r
|
|
.db I_CALL,0xa, 'N', 3, 0b11000100 , 0 ; CALL cc, NN
|
|
.db I_CALL,'N', 0, 0, 0xcd , 0 ; CALL NN
|
|
.db I_CCF, 0, 0, 0, 0x3f , 0 ; CCF
|
|
.db I_CP, 'l', 0, 0, 0xbe , 0 ; CP (HL)
|
|
.db I_CP, 0xb, 0, 0, 0b10111000 , 0 ; CP r
|
|
.db I_CP, 'n', 0, 0, 0xfe , 0 ; CP n
|
|
.db I_CP, 'x', 0, 0, 0xdd, 0xbe ; CP (IX+d)
|
|
.db I_CP, 'y', 0, 0, 0xfd, 0xbe ; CP (IY+d)
|
|
.db I_CPD, 0, 0, 0, 0xed, 0xa9 ; CPD
|
|
.db I_CPDR,0, 0, 0, 0xed, 0xb9 ; CPDR
|
|
.db I_CPI, 0, 0, 0, 0xed, 0xa1 ; CPI
|
|
.db I_CPIR,0, 0, 0, 0xed, 0xb1 ; CPIR
|
|
.db I_CPL, 0, 0, 0, 0x2f , 0 ; CPL
|
|
.db I_DAA, 0, 0, 0, 0x27 , 0 ; DAA
|
|
.db I_DEC, 'l', 0, 0, 0x35 , 0 ; DEC (HL)
|
|
.db I_DEC, 'X', 0, 0, 0xdd, 0x2b ; DEC IX
|
|
.db I_DEC, 'x', 0, 0, 0xdd, 0x35 ; DEC (IX+d)
|
|
.db I_DEC, 'Y', 0, 0, 0xfd, 0x2b ; DEC IY
|
|
.db I_DEC, 'y', 0, 0, 0xfd, 0x35 ; DEC (IY+d)
|
|
.db I_DEC, 0xb, 0, 3, 0b00000101 , 0 ; DEC r
|
|
.db I_DEC, 0x3, 0, 4, 0b00001011 , 0 ; DEC ss
|
|
.db I_DI, 0, 0, 0, 0xf3 , 0 ; DI
|
|
.db I_DJNZ,'n', 0, 0x80, 0x10 , 0 ; DJNZ e
|
|
.db I_EI, 0, 0, 0, 0xfb , 0 ; EI
|
|
.db I_EX, 'p', 'h', 0, 0xe3 , 0 ; EX (SP), HL
|
|
.db I_EX, 'p', 'X', 0, 0xdd, 0xe3 ; EX (SP), IX
|
|
.db I_EX, 'p', 'Y', 0, 0xfd, 0xe3 ; EX (SP), IY
|
|
.db I_EX, 'a', 'f', 0, 0x08 , 0 ; EX AF, AF'
|
|
.db I_EX, 'd', 'h', 0, 0xeb , 0 ; EX DE, HL
|
|
.db I_EXX, 0, 0, 0, 0xd9 , 0 ; EXX
|
|
.db I_HALT,0, 0, 0, 0x76 , 0 ; HALT
|
|
.db I_IM, 'n', 0, 0x20 \ .dw handleIM ; IM {0,1,2}
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.db I_IN, 'A', 'm', 0, 0xdb , 0 ; IN A, (n)
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.db I_IN, 0xb, 'k', 0x43, 0xed, 0b01000000 ; IN r, (C)
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.db I_INC, 'l', 0, 0, 0x34 , 0 ; INC (HL)
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.db I_INC, 'X', 0, 0, 0xdd , 0x23 ; INC IX
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.db I_INC, 'x', 0, 0, 0xdd , 0x34 ; INC (IX+d)
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.db I_INC, 'Y', 0, 0, 0xfd , 0x23 ; INC IY
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.db I_INC, 'y', 0, 0, 0xfd , 0x34 ; INC (IY+d)
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.db I_INC, 0xb, 0, 3, 0b00000100 , 0 ; INC r
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.db I_INC, 0x3, 0, 4, 0b00000011 , 0 ; INC ss
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.db I_IND, 0, 0, 0, 0xed, 0xaa ; IND
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.db I_INDR,0, 0, 0, 0xed, 0xba ; INDR
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.db I_INI, 0, 0, 0, 0xed, 0xa2 ; INI
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.db I_INIR,0, 0, 0, 0xed, 0xb2 ; INIR
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.db I_JP, 'l', 0, 0, 0xe9 , 0 ; JP (HL)
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.db I_JP, 0xa, 'N', 3, 0b11000010 , 0 ; JP cc, NN
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.db I_JP, 'N', 0, 0, 0xc3 , 0 ; JP NN
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.db I_JP, 'x', 0, 0x20 \ .dw handleJPIX ; JP (IX)
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.db I_JP, 'y', 0, 0x20 \ .dw handleJPIY ; JP (IY)
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.db I_JR, 'n', 0, 0x80, 0x18 , 0 ; JR e
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.db I_JR, 'C', 'n', 0x80, 0x38 , 0 ; JR C, e
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.db I_JR, '=', 'n', 0x80, 0x30 , 0 ; JR NC, e
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.db I_JR, 'Z', 'n', 0x80, 0x28 , 0 ; JR Z, e
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.db I_JR, 'z', 'n', 0x80, 0x20 , 0 ; JR NZ, e
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.db I_LD, 'c', 'A', 0, 0x02 , 0 ; LD (BC), A
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.db I_LD, 'e', 'A', 0, 0x12 , 0 ; LD (DE), A
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.db I_LD, 'A', 'c', 0, 0x0a , 0 ; LD A, (BC)
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.db I_LD, 'A', 'e', 0, 0x1a , 0 ; LD A, (DE)
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.db I_LD, 's', 'h', 0, 0xf9 , 0 ; LD SP, HL
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.db I_LD, 'A', 'I', 0, 0xed, 0x57 ; LD A, I
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.db I_LD, 'I', 'A', 0, 0xed, 0x47 ; LD I, A
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.db I_LD, 'A', 'R', 0, 0xed, 0x5f ; LD A, R
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.db I_LD, 'R', 'A', 0, 0xed, 0x4f ; LD R, A
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.db I_LD, 'l', 0xb, 0, 0b01110000 , 0 ; LD (HL), r
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.db I_LD, 0xb, 'l', 3, 0b01000110 , 0 ; LD r, (HL)
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.db I_LD, 'l', 'n', 0, 0x36 , 0 ; LD (HL), n
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.db I_LD, 0xb, 'n', 3, 0b00000110 , 0 ; LD r, n
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.db I_LD, 0xb, 0xb, 0x20 \ .dw handleLDrr ; LD r, r'
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.db I_LD, 0x3, 'N', 4, 0b00000001 , 0 ; LD dd, n
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.db I_LD, 'M', 'A', 0, 0x32 , 0 ; LD (NN), A
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.db I_LD, 'A', 'M', 0, 0x3a , 0 ; LD A, (NN)
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.db I_LD, 'M', 'h', 0, 0x22 , 0 ; LD (NN), HL
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.db I_LD, 'h', 'M', 0, 0x2a , 0 ; LD HL, (NN)
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.db I_LD, 'M', 'X', 0, 0xdd, 0x22 ; LD (NN), IX
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.db I_LD, 'X', 'M', 0, 0xdd, 0x2a ; LD IX, (NN)
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.db I_LD, 'M', 'Y', 0, 0xfd, 0x22 ; LD (NN), IY
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.db I_LD, 'Y', 'M', 0, 0xfd, 0x2a ; LD IY, (NN)
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.db I_LD, 'M', 0x3, 0x44, 0xed, 0b01000011 ; LD (NN), dd
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.db I_LD, 0x3, 'M', 0x44, 0xed, 0b01001011 ; LD dd, (NN)
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.db I_LD, 'x', 'n', 0x20 \ .dw handleLDIXn ; LD (IX+d), n
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.db I_LD, 'y', 'n', 0x20 \ .dw handleLDIYn ; LD (IY+d), n
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.db I_LD, 'x', 0xb, 0x20 \ .dw handleLDIXr ; LD (IX+d), r
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.db I_LD, 'y', 0xb, 0x20 \ .dw handleLDIYr ; LD (IY+d), r
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.db I_LDD, 0, 0, 0, 0xed, 0xa8 ; LDD
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.db I_LDDR,0, 0, 0, 0xed, 0xb8 ; LDDR
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.db I_LDI, 0, 0, 0, 0xed, 0xa0 ; LDI
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.db I_LDIR,0, 0, 0, 0xed, 0xb0 ; LDIR
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.db I_NEG, 0, 0, 0, 0xed, 0x44 ; NEG
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.db I_NOP, 0, 0, 0, 0x00 , 0 ; NOP
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.db I_OR, 'l', 0, 0, 0xb6 , 0 ; OR (HL)
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.db I_OR, 0xb, 0, 0, 0b10110000 , 0 ; OR r
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.db I_OR, 'n', 0, 0, 0xf6 , 0 ; OR n
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.db I_OR, 'x', 0, 0, 0xdd, 0xb6 ; OR (IX+d)
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.db I_OR, 'y', 0, 0, 0xfd, 0xb6 ; OR (IY+d)
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.db I_OTDR,0, 0, 0, 0xed, 0xbb ; OTDR
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.db I_OTIR,0, 0, 0, 0xed, 0xb3 ; OTIR
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.db I_OUT, 'm', 'A', 0, 0xd3 , 0 ; OUT (n), A
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.db I_OUT, 'k', 0xb, 0x43, 0xed, 0b01000001 ; OUT (C), r
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.db I_POP, 'X', 0, 0, 0xdd, 0xe1 ; POP IX
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.db I_POP, 'Y', 0, 0, 0xfd, 0xe1 ; POP IY
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.db I_POP, 0x1, 0, 4, 0b11000001 , 0 ; POP qq
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.db I_PUSH,'X', 0, 0, 0xdd, 0xe5 ; PUSH IX
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.db I_PUSH,'Y', 0, 0, 0xfd, 0xe5 ; PUSH IY
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.db I_PUSH,0x1, 0, 4, 0b11000101 , 0 ; PUSH qq
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.db I_RET, 0, 0, 0, 0xc9 , 0 ; RET
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.db I_RET, 0xa, 0, 3, 0b11000000 , 0 ; RET cc
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.db I_RETI,0, 0, 0, 0xed, 0x4d ; RETI
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.db I_RETN,0, 0, 0, 0xed, 0x45 ; RETN
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.db I_RLA, 0, 0, 0, 0x17 , 0 ; RLA
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.db I_RLCA,0, 0, 0, 0x07 , 0 ; RLCA
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.db I_RRA, 0, 0, 0, 0x1f , 0 ; RRA
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.db I_RRCA,0, 0, 0, 0x0f , 0 ; RRCA
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.db I_SBC, 'A', 'l', 0, 0x9e , 0 ; SBC A, (HL)
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.db I_SBC, 'A', 0xb, 0, 0b10011000 , 0 ; SBC A, r
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.db I_SCF, 0, 0, 0, 0x37 , 0 ; SCF
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.db I_SUB, 'A', 'l', 0, 0x96 , 0 ; SUB A, (HL)
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.db I_SUB, 'A', 0xb, 0, 0b10010000 , 0 ; SUB A, r
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.db I_SUB, 'n', 0, 0, 0xd6 , 0 ; SUB n
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|
.db I_XOR, 'l', 0, 0, 0xae , 0 ; XOR (HL)
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.db I_XOR, 0xb, 0, 0, 0b10101000 , 0 ; XOR r
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; *** Variables ***
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; Args are 3 bytes: argspec, then values of numerical constants (when that's
|
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; appropriate)
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curArg1:
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.db 0, 0, 0
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curArg2:
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.db 0, 0, 0
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instrUpcode:
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.db 0, 0, 0, 0
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