zasm: Add support for (NN) constants
This commit is contained in:
Virgil Dupras
parent
e1d6178457
commit
c5c8369ce9
@ -4,7 +4,7 @@
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; Number of rows in the argspec table
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ARGSPEC_TBL_CNT .equ 27
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; Number of rows in the primary instructions table
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INSTR_TBLP_CNT .equ 56
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INSTR_TBLP_CNT .equ 58
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; size in bytes of each row in the primary instructions table
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INSTR_TBLP_ROWSIZE .equ 8
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@ -33,6 +33,45 @@ rlaX:
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djnz .loop
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ret
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; If string at (HL) starts with ( and ends with ), "enter" into the parens
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; (advance HL and put a null char at the end of the string) and set Z.
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; Otherwise, do nothing and reset Z.
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enterParens:
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ld a, (hl)
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cp '('
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ret nz ; nothing to do
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push hl
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ld a, 0 ; look for null char
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; advance until we get null
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.loop:
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cpi
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jp z, .found
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jr .loop
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.found:
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dec hl ; cpi over-advances. go back to null-char
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dec hl ; looking at the last char before null
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ld a, (hl)
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cp ')'
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jr nz, .doNotEnter
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; We have parens. While we're here, let's put a null
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xor a
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ld (hl), a
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pop hl ; back at the beginning. Let's advance.
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inc hl
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cp a ; ensure Z
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ret ; we're good!
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.doNotEnter:
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pop hl
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call unsetZ
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ret
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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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; Parse the decimal char at A and extract it's 0-9 numerical value. Put the
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; result in A.
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;
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@ -49,10 +88,20 @@ parseDecimal:
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; Parses the string at (HL) and returns the 16-bit value in IX.
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; As soon as the number doesn't fit 16-bit any more, parsing stops and the
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; number is invalid. If the number is valid, Z is set, otherwise, unset.
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; If (HL) contains a number inside parens, we properly enter into it.
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; Upon successful return, A is set to 'N' for a parens-less number, 'M' for
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; a number inside parens.
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parseNumber:
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push hl
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push de
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push bc
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; Let's see if we have parens and already set the A result in B.
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ld b, 'N' ; if no parens
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call enterParens
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jr nz, .noparens
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ld b, 'M' ; we have parens and entered it.
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.noparens:
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ld ix, 0
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.loop:
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ld a, (hl)
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@ -87,6 +136,8 @@ parseNumber:
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.error:
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call unsetZ
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.end:
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ld a, b
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pop bc
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pop de
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pop hl
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ret
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@ -262,13 +313,12 @@ parseArg:
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call JUMP_ADDDE
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djnz .loop1
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; We exhausted the argspecs. Let's see if it's a number
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; We exhausted the argspecs. Let's see if it's a number. This sets
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; A to 'N' or 'M'
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call parseNumber
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jr nz, .notanumber
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; Alright, we have a parsed number in IX. We're done.
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ld a, 'N'
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jr .end
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.notanumber:
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jr z, .end ; Alright, we have a parsed number in IX. We're
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; done.
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; not a number
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ld a, 0xff
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jr .end
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.found:
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@ -375,16 +425,18 @@ matchArg:
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cp a, (hl)
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ret z
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; not an exact match, let's check for numerical constants.
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call JUMP_UPCASE
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cp 'N'
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jr z, .expectsNumber
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cp 'n'
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cp 'M'
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jr z, .expectsNumber
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jr .notNumber
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.expectsNumber:
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ld a, (hl)
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cp 'N' ; In parsed arg, we don't have 'n', only 'N'
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ret ; whether we match or not, the result of Z is the good
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; one
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call checkNOrM ; In parsed arg, we don't have 'n' or 'm', only
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; 'N' and 'M'
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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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@ -516,16 +568,20 @@ parseLine:
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push hl ; we use HL to point to the currently read arg
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ld a, (ix+4) ; first argspec
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ld hl, curArg1
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cp 'N'
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call checkNOrM
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jr z, .withWord
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cp 'n'
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jr z, .withByte
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cp 'm'
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jr z, .withByte
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ld a, (ix+5) ; second argspec
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ld hl, curArg2
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cp 'N'
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call checkNOrM
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jr z, .withWord
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cp 'n'
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jr z, .withByte
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cp 'm'
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jr z, .withByte
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; nope, no number, aright, only one opcode
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ld a, 1
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jr .end
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@ -653,6 +709,7 @@ instrTBlPrimary:
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.db "EX",0,0, 'd', 'h', 0, 0xeb ; EX DE, HL
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.db "EXX", 0, 0, 0, 0, 0xd9 ; EXX
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.db "HALT", 0, 0, 0, 0x76 ; HALT
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.db "IN",0,0, 'A', 'm', 0, 0xdb ; IN A, (n)
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.db "INC", 0, 'l', 0, 0, 0x34 ; INC (HL)
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.db "INC", 0, 0xb, 0, 3, 0b00000100 ; INC r
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.db "INC", 0, 0x3, 0, 4, 0b00000011 ; INC s
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@ -671,6 +728,7 @@ instrTBlPrimary:
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.db "NOP", 0, 0, 0, 0, 0x00 ; NOP
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.db "OR",0,0, 'l', 0, 0, 0xb6 ; OR (HL)
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.db "OR",0,0, 0xb, 0, 0, 0b10110000 ; OR r
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.db "OUT", 0, 'm', 'A', 0, 0xd3 ; OUT (n), A
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.db "POP", 0, 0x1, 0, 4, 0b11000001 ; POP qq
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.db "PUSH", 0x1, 0, 4, 0b11000101 ; PUSH qq
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.db "RET", 0, 0xa, 0, 3, 0b11000000 ; RET cc
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