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collapseos/apps/zasm/instr.asm
Virgil Dupras d1735c3a73 zasm: remove last remnants of "old style" variables 
This makes zasm suitable to run from ROM.
2019-07-25 14:02:04 -04:00

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; *** Consts ***
; Number of rows in the argspec table
.equ ARGSPEC_TBL_CNT 33
; Number of rows in the primary instructions table
.equ INSTR_TBL_CNT 162
; size in bytes of each row in the primary instructions table
.equ INSTR_TBL_ROWSIZE 6
; Instruction IDs They correspond to the index of the table in instrNames
.equ I_ADC 0x00
.equ I_ADD 0x01
.equ I_AND 0x02
.equ I_BIT 0x03
.equ I_CALL 0x04
.equ I_CCF 0x05
.equ I_CP 0x06
.equ I_CPD 0x07
.equ I_CPDR 0x08
.equ I_CPI 0x09
.equ I_CPIR 0x0a
.equ I_CPL 0x0b
.equ I_DAA 0x0c
.equ I_DEC 0x0d
.equ I_DI 0x0e
.equ I_DJNZ 0x0f
.equ I_EI 0x10
.equ I_EX 0x11
.equ I_EXX 0x12
.equ I_HALT 0x13
.equ I_IM 0x14
.equ I_IN 0x15
.equ I_INC 0x16
.equ I_IND 0x17
.equ I_INDR 0x18
.equ I_INI 0x19
.equ I_INIR 0x1a
.equ I_JP 0x1b
.equ I_JR 0x1c
.equ I_LD 0x1d
.equ I_LDD 0x1e
.equ I_LDDR 0x1f
.equ I_LDI 0x20
.equ I_LDIR 0x21
.equ I_NEG 0x22
.equ I_NOP 0x23
.equ I_OR 0x24
.equ I_OTDR 0x25
.equ I_OTIR 0x26
.equ I_OUT 0x27
.equ I_POP 0x28
.equ I_PUSH 0x29
.equ I_RES 0x2a
.equ I_RET 0x2b
.equ I_RETI 0x2c
.equ I_RETN 0x2d
.equ I_RL 0x2e
.equ I_RLA 0x2f
.equ I_RLC 0x30
.equ I_RLCA 0x31
.equ I_RR 0x32
.equ I_RRA 0x33
.equ I_RRC 0x34
.equ I_RRCA 0x35
.equ I_SBC 0x36
.equ I_SCF 0x37
.equ I_SET 0x38
.equ I_SLA 0x39
.equ I_SRL 0x3a
.equ I_SUB 0x3b
.equ I_XOR 0x3c
; *** Variables ***
; Args are 3 bytes: argspec, then values of numerical constants (when that's
; appropriate)
.equ INS_CURARG1 INS_RAMSTART
.equ INS_CURARG2 INS_CURARG1+3
.equ INS_UPCODE INS_CURARG2+3
.equ INS_RAMEND INS_UPCODE+4
; *** Code ***
; Checks whether A is 'N' or 'M'
checkNOrM:
cp 'N'
ret z
cp 'M'
ret
; Checks whether A is 'n', 'm', 'x' or 'y'
checknmxy:
cp 'n'
ret z
cp 'm'
ret z
cp 'x'
ret z
cp 'y'
ret
; Reads string in (HL) and returns the corresponding ID (I_*) in A. Sets Z if
; there's a match.
getInstID:
push bc
push de
ld b, I_XOR+1 ; I_XOR is the last
ld c, 4
ld de, instrNames
call findStringInList
pop de
pop bc
ret
; Parse the string at (HL) and check if it starts with IX+, IY+, IX- or IY-.
; Sets Z if yes, unset if no.
parseIXY:
push hl
ld a, (hl)
call upcase
cp 'I'
jr nz, .end ; Z already unset
inc hl
ld a, (hl)
call upcase
cp 'X'
jr z, .match1
cp 'Y'
jr z, .match1
jr .end ; Z already unset
.match1:
; Alright, we have IX or IY. Let's see if we have + or - next.
inc hl
ld a, (hl)
cp '+'
jr z, .end ; Z is already set
cp '-'
; The value of Z at this point is our final result
.end:
pop hl
ret
; find argspec for string at (HL). Returns matching argspec in A.
; Return value 0xff holds a special meaning: arg is not empty, but doesn't match
; any argspec (A == 0 means arg is empty). A return value of 0xff means an
; error.
;
; If the parsed argument is a number constant, 'N' is returned and IX contains
; the value of that constant.
parseArg:
call strlen
or a
ret z ; empty string? A already has our result: 0
push bc
push de
push hl
; We always initialize IX to zero so that non-numerical args end up with
; a clean zero.
ld ix, 0
ld de, argspecTbl
; DE now points the the "argspec char" part of the entry, but what
; we're comparing in the loop is the string next to it. Let's offset
; DE by one so that the loop goes through strings.
inc de
ld b, ARGSPEC_TBL_CNT
.loop1:
ld a, 4
call strncmpI
jr z, .found ; got it!
ld a, 5
call addDE
djnz .loop1
; We exhausted the argspecs. Let's see if we're inside parens.
call enterParens
jr z, .withParens
; (HL) has no parens
call .maybeParseExpr
jr nz, .nomatch
; We have a proper number in no parens. Number in IX.
ld a, 'N'
jr .end
.withParens:
ld c, 'M' ; C holds the argspec type until we reach
; .numberInParens
; We have parens. First, let's see if we have a (IX+d) type of arg.
call parseIXY
jr nz, .parseNumberInParens ; not I{X,Y}. just parse number.
; We have IX+/IY+/IX-/IY-.
; note: the "-" part isn't supported yet.
inc hl ; (HL) now points to X or Y
ld a, (hl)
call upcase
inc hl ; advance HL to the number part
inc hl ; this is the number
cp 'Y'
jr nz, .notY
ld c, 'y'
jr .parseNumberInParens
.notY:
ld c, 'x'
.parseNumberInParens:
call .maybeParseExpr
jr nz, .nomatch
; We have a proper number in parens. Number in IX
ld a, c ; M, x, or y
jr .end
.nomatch:
; We get no match
ld a, 0xff
jr .end
.found:
; found the matching argspec row. Our result is one byte left of DE.
dec de
ld a, (de)
.end:
pop hl
pop de
pop bc
ret
.maybeParseExpr:
; Before we try to parse expr in (HL), first check if we're in first
; pass if we are, skip parseExpr. Most of the time, that parse is
; harmless, but in some cases it causes false failures. For example,
; a "-" operator can cause is to falsely overflow and generate
; truncation error.
call zasmIsFirstPass
ret z
jp parseExpr
; Returns, with Z, whether A is a groupId
isGroupId:
cp 0xc ; max group id + 1
jr nc, .notgroup ; >= 0xc? not a group
cp 0
jr z, .notgroup ; 0? not supposed to happen. something's wrong.
; A is a group. ensure Z is set
cp a
ret
.notgroup:
call unsetZ
ret
; Find argspec A in group id H.
; Set Z according to whether we found the argspec
; If found, the value in A is the argspec value in the group (its index).
findInGroup:
push bc
push hl
or a ; is our arg empty? If yes, we have nothing to do
jr z, .notfound
push af
ld a, h
cp 0xa
jr z, .specialGroupCC
cp 0xb
jr z, .specialGroupABCDEHL
jr nc, .notfound ; > 0xb? not a group
pop af
; regular group
push de
ld de, argGrpTbl
; group ids start at 1. decrease it, then multiply by 4 to have a
; proper offset in argGrpTbl
dec h
push af
ld a, h
rla
rla
call addDE ; At this point, DE points to our group
pop af
ex de, hl ; And now, HL points to the group
pop de
ld bc, 4
jr .find
.specialGroupCC:
ld hl, argGrpCC
jr .specialGroupEnd
.specialGroupABCDEHL:
ld hl, argGrpABCDEHL
.specialGroupEnd:
pop af ; from the push af just before the special group check
ld bc, 8
.find:
; This part is common to regular and special group. We expect HL to
; point to the group and BC to contain its length.
push bc ; save the start value loop index so we can sub
.loop:
cpi
jr z, .found
jp po, .notfound
jr .loop
.found:
; we found our result! Now, what we want to put in A is the index of
; the found argspec.
pop hl ; we pop from the "push bc" above. L is now 4 or 8
ld a, l
sub c
dec a ; cpi DECs BC even when there's a match, so C == the
; number of iterations we've made. But our index is
; zero-based (1 iteration == 0 index).
cp a ; ensure Z is set
jr .end
.notfound:
pop bc ; from the push bc in .find
call unsetZ
.end:
pop hl
pop bc
ret
; Compare argspec from instruction table in A with argument in (HL).
; For constant args, it's easy: if A == (HL), it's a success.
; If it's not this, then we check if it's a numerical arg.
; If A is a group ID, we do something else: we check that (HL) exists in the
; groupspec (argGrpTbl). Moreover, we go and write the group's "value" (index)
; in (HL+1). This will save us significant processing later in getUpcode.
; Set Z according to whether we match or not.
matchArg:
cp (hl)
ret z
; not an exact match. Before we continue: is A zero? Because if it is,
; we have to stop right here: no match possible.
or a
jr nz, .checkIfNumber ; not a zero, we can continue
; zero, stop here
call unsetZ
ret
.checkIfNumber:
; not an exact match, let's check for numerical constants.
call upcase
call checkNOrM
jr z, .expectsNumber
jr .notNumber
.expectsNumber:
; Our argument is a number N or M. Never a lower-case version. At this
; point in the processing, we don't care about whether N or M is upper,
; we do truncation tests later. So, let's just perform the same == test
; but in a case-insensitive way instead
cp (hl)
ret ; whether we match or not, the result of Z is
; the good one.
.notNumber:
; A bit of a delicate situation here: we want A to go in H but also
; (HL) to go in A. If not careful, we overwrite each other. EXX is
; necessary to avoid invoving other registers.
push hl
exx
ld h, a
push hl
exx
ld a, (hl)
pop hl
call findInGroup
pop hl
ret nz
; we found our group? let's write down its "value" in (HL+1). We hold
; this value in A at the moment.
inc hl
ld (hl), a
dec hl
ret
; Compare primary row at (DE) with ID in A. Sets Z flag if there's a match.
matchPrimaryRow:
push hl
push ix
push de \ pop ix
cp (ix)
jr nz, .end
; name matches, let's see the rest
ld hl, INS_CURARG1
ld a, (ix+1)
call matchArg
jr nz, .end
ld hl, INS_CURARG2
ld a, (ix+2)
call matchArg
.end:
pop ix
pop hl
ret
; *** Special opcodes ***
; The special upcode handling routines below all have the same signature.
; Instruction row is at IX and we're expected to perform the same task as
; getUpcode. The number of bytes, however, must go in C instead of A
; No need to preserve HL, DE, BC and IX: it's handled by getUpcode already.
; Handle like a regular "JP (IX+d)" except that we refuse any displacement: if
; a displacement is specified, we error out.
handleJPIX:
ld a, 0xdd
jr handleJPIXY
handleJPIY:
ld a, 0xfd
handleJPIXY:
ld (INS_UPCODE), a
ld a, (INS_CURARG1+1)
cp 0 ; numerical argument *must* be zero
jr nz, .error
; ok, we're good
ld a, 0xe9 ; second upcode
ld (INS_UPCODE+1), a
ld c, 2
ret
.error:
ld c, 0
ret
; Handle the first argument of BIT. Sets Z if first argument is valid, unset it
; if there's an error.
handleBIT:
ld a, (INS_CURARG1+1)
cp 8
jr nc, .error ; >= 8? error
; We're good
cp a ; ensure Z
ret
.error:
ld c, 0
jp unsetZ
handleBITHL:
ld b, 0b01000110
jr _handleBITHL
handleSETHL:
ld b, 0b11000110
jr _handleBITHL
handleRESHL:
ld b, 0b10000110
_handleBITHL:
call handleBIT
ret nz ; error
ld a, 0xcb ; first upcode
ld (INS_UPCODE), a
ld a, (INS_CURARG1+1) ; 0-7
rla
rla
rla
or b ; 2nd upcode
ld (INS_UPCODE+1), a
ld c, 2
ret
handleBITIX:
ld a, 0xdd
ld b, 0b01000110
jr _handleBITIXY
handleBITIY:
ld a, 0xfd
ld b, 0b01000110
jr _handleBITIXY
handleSETIX:
ld a, 0xdd
ld b, 0b11000110
jr _handleBITIXY
handleSETIY:
ld a, 0xfd
ld b, 0b11000110
jr _handleBITIXY
handleRESIX:
ld a, 0xdd
ld b, 0b10000110
jr _handleBITIXY
handleRESIY:
ld a, 0xfd
ld b, 0b10000110
_handleBITIXY:
ld (INS_UPCODE), a ; first upcode
call handleBIT
ret nz ; error
ld a, 0xcb ; 2nd upcode
ld (INS_UPCODE+1), a
ld a, (INS_CURARG2+1) ; IXY displacement
ld (INS_UPCODE+2), a
ld a, (INS_CURARG1+1) ; 0-7
rla
rla
rla
or b ; 4th upcode
ld (INS_UPCODE+3), a
ld c, 4
ret
handleBITR:
ld b, 0b01000000
jr _handleBITR
handleSETR:
ld b, 0b11000000
jr _handleBITR
handleRESR:
ld b, 0b10000000
_handleBITR:
call handleBIT
ret nz ; error
; get group value
ld a, (INS_CURARG2+1) ; group value
ld c, a
; write first upcode
ld a, 0xcb ; first upcode
ld (INS_UPCODE), a
; get bit value
ld a, (INS_CURARG1+1) ; 0-7
rla
rla
rla
; Now we have group value in stack, bit value in A (properly shifted)
; and we want to OR them together
or c ; Now we have our ORed value
or b ; and with our "base" value and we're good!
ld (INS_UPCODE+1), a
ld c, 2
ret
handleIM:
ld a, (INS_CURARG1+1)
cp 0
jr z, .im0
cp 1
jr z, .im1
cp 2
jr z, .im2
; error
ld c, 0
ret
.im0:
ld a, 0x46
jr .proceed
.im1:
ld a, 0x56
jr .proceed
.im2:
ld a, 0x5e
.proceed:
ld (INS_UPCODE+1), a
ld a, 0xed
ld (INS_UPCODE), a
ld c, 2
ret
handleLDIXn:
ld a, 0xdd
jr handleLDIXYn
handleLDIYn:
ld a, 0xfd
handleLDIXYn:
ld (INS_UPCODE), a
ld a, 0x36 ; second upcode
ld (INS_UPCODE+1), a
ld a, (INS_CURARG1+1) ; IXY displacement
ld (INS_UPCODE+2), a
ld a, (INS_CURARG2+1) ; N
ld (INS_UPCODE+3), a
ld c, 4
ret
handleLDIXr:
ld a, 0xdd
jr handleLDIXYr
handleLDIYr:
ld a, 0xfd
handleLDIXYr:
ld (INS_UPCODE), a
ld a, (INS_CURARG2+1) ; group value
or 0b01110000 ; second upcode
ld (INS_UPCODE+1), a
ld a, (INS_CURARG1+1) ; IXY displacement
ld (INS_UPCODE+2), a
ld c, 3
ret
handleLDrIX:
ld a, 0xdd
jr handleLDrIXY
handleLDrIY:
ld a, 0xfd
handleLDrIXY:
ld (INS_UPCODE), a
ld a, (INS_CURARG1+1) ; group value
rla \ rla \ rla
or 0b01000110 ; second upcode
ld (INS_UPCODE+1), a
ld a, (INS_CURARG2+1) ; IXY displacement
ld (INS_UPCODE+2), a
ld c, 3
ret
handleLDrr:
; first argument is displaced by 3 bits, second argument is not
; displaced and we or that with a leading 0b01000000
ld a, (INS_CURARG1+1) ; group value
rla
rla
rla
ld c, a ; store it
ld a, (INS_CURARG2+1) ; other group value
or c
or 0b01000000
ld (INS_UPCODE), a
ld c, 1
ret
; Compute the upcode for argspec row at (DE) and arguments in curArg{1,2} and
; writes the resulting upcode in INS_UPCODE. A is the number if bytes written
; to INS_UPCODE.
; A is zero on error. The only thing that can go wrong in this routine is
; overflow.
getUpcode:
push ix
push de
push hl
push bc
; First, let's go in IX mode. It's easier to deal with offsets here.
push de \ pop ix
; Are we a "special instruction"?
bit 5, (ix+3)
jr z, .normalInstr ; not set: normal instruction
; We are a special instruction. Fetch handler (little endian, remember).
ld l, (ix+4)
ld h, (ix+5)
call callHL
; We have our result written in INS_UPCODE 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 (INS_UPCODE), a
ld de, INS_UPCODE ; 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 c, 1 ; C holds our upcode count
; Now, let's determine if we have one or two upcode. As a general rule,
; we simply have to check if (ix+5) == 0, which means one upcode.
; However, some two-upcodes instructions have a 0 (ix+5) because they
; expect group OR-ing into it and all other bits are zero. See "RLC r".
; To handle those cases, we *also* check for Bit 6 in (ix+3).
ld a, (ix+5) ; second upcode
or a ; do we have a second upcode?
jr nz, .twoUpcodes
bit 6, (ix+3)
jr z, .onlyOneUpcode ; not set: single upcode
.twoUpcodes:
; we have two upcodes
ld (de), a
inc de
inc c
.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, INS_CURARG2
jr .isGroup
.firstArgIsGroup:
ld hl, INS_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 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 (INS_UPCODE+1), a
jr .writeExtraBytes
.firstUpcode:
or (ix+4) ; first upcode
ld (INS_UPCODE), 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 INS_UPCODE).
ld a, (ix+1) ; first argspec
ld hl, INS_CURARG1
call checkNOrM
jr z, .withWord
call checknmxy
jr z, .withByte
ld a, (ix+2) ; second argspec
ld hl, INS_CURARG2
call checkNOrM
jr z, .withWord
call checknmxy
jr z, .withByte
; nope, no number, alright, we're finished here
jr .end
.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 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.
inc c ; one extra byte is written
call zasmIsFirstPass
jr z, .end
; We're on second pass
push de ; Don't let go of this, that's our dest
push hl
call zasmGetPC ; --> HL
ex de, hl
pop hl
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 .end
.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
push bc
ldi
pop bc
inc c
jr .end
.withWord:
inc hl ; HL now points to LSB
; Clear to proceed. HL already points to our number
push bc
ldi ; LSB written, we point to MSB now
ldi ; MSB written
pop bc
inc c ; two extra bytes are written
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
push hl
push ix \ pop hl
call writeHLinDE
pop hl
cp a ; ensure Z is set
ret
.error:
ld a, ERR_BAD_ARG
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. On error, A contains an error code (ERR_*)
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 (INS_CURARG1), a
ld (INS_CURARG2), a
call readWord
jr nz, .nomorearg
ld de, INS_CURARG1
call processArg
jr nz, .error ; A is set to error
call readComma
jr nz, .nomorearg
call readWord
jr nz, .badfmt
ld de, INS_CURARG2
call processArg
jr nz, .error ; A is set to 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 signature match
ld a, ERR_BAD_ARG
jr .error
.match:
; We have our matching instruction row. We're getting pretty near our
; goal here!
call getUpcode
or a ; is zero?
jr z, .overflow
ld b, a ; save output byte count
ld hl, INS_UPCODE
.loopWrite:
ld a, (hl)
call ioPutC
jr nz, .ioError
inc hl
djnz .loopWrite
cp a ; ensure Z
jr .end
.ioError:
ld a, SHELL_ERR_IO_ERROR
jr .error
.overflow:
ld a, ERR_OVFL
jr .error
.badfmt:
ld a, ERR_BAD_FMT
.error:
; A is set to error already
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 "RES", 0
.db "RET", 0
.db "RETI"
.db "RETN"
.db "RL", 0, 0
.db "RLA", 0
.db "RLC", 0
.db "RLCA"
.db "RR", 0, 0
.db "RRA", 0
.db "RRC", 0
.db "RRCA"
.db "SBC", 0
.db "SCF", 0
.db "SET", 0
.db "SLA", 0
.db "SRL", 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}
.db I_IN, 'A', 'm', 0, 0xdb , 0 ; IN A, (n)
.db I_IN, 0xb, 'k', 0x43, 0xed, 0b01000000 ; IN r, (C)
.db I_INC, 'l', 0, 0, 0x34 , 0 ; INC (HL)
.db I_INC, 'X', 0, 0, 0xdd , 0x23 ; INC IX
.db I_INC, 'x', 0, 0, 0xdd , 0x34 ; INC (IX+d)
.db I_INC, 'Y', 0, 0, 0xfd , 0x23 ; INC IY
.db I_INC, 'y', 0, 0, 0xfd , 0x34 ; INC (IY+d)
.db I_INC, 0xb, 0, 3, 0b00000100 , 0 ; INC r
.db I_INC, 0x3, 0, 4, 0b00000011 , 0 ; INC ss
.db I_IND, 0, 0, 0, 0xed, 0xaa ; IND
.db I_INDR,0, 0, 0, 0xed, 0xba ; INDR
.db I_INI, 0, 0, 0, 0xed, 0xa2 ; INI
.db I_INIR,0, 0, 0, 0xed, 0xb2 ; INIR
.db I_JP, 'l', 0, 0, 0xe9 , 0 ; JP (HL)
.db I_JP, 0xa, 'N', 3, 0b11000010 , 0 ; JP cc, NN
.db I_JP, 'N', 0, 0, 0xc3 , 0 ; JP NN
.db I_JP, 'x', 0, 0x20 \ .dw handleJPIX ; JP (IX)
.db I_JP, 'y', 0, 0x20 \ .dw handleJPIY ; JP (IY)
.db I_JR, 'n', 0, 0x80, 0x18 , 0 ; JR e
.db I_JR, 'C', 'n', 0x80, 0x38 , 0 ; JR C, e
.db I_JR, '=', 'n', 0x80, 0x30 , 0 ; JR NC, e
.db I_JR, 'Z', 'n', 0x80, 0x28 , 0 ; JR Z, e
.db I_JR, 'z', 'n', 0x80, 0x20 , 0 ; JR NZ, e
.db I_LD, 'c', 'A', 0, 0x02 , 0 ; LD (BC), A
.db I_LD, 'e', 'A', 0, 0x12 , 0 ; LD (DE), A
.db I_LD, 'A', 'c', 0, 0x0a , 0 ; LD A, (BC)
.db I_LD, 'A', 'e', 0, 0x1a , 0 ; LD A, (DE)
.db I_LD, 's', 'h', 0, 0xf9 , 0 ; LD SP, HL
.db I_LD, 'A', 'I', 0, 0xed, 0x57 ; LD A, I
.db I_LD, 'I', 'A', 0, 0xed, 0x47 ; LD I, A
.db I_LD, 'A', 'R', 0, 0xed, 0x5f ; LD A, R
.db I_LD, 'R', 'A', 0, 0xed, 0x4f ; LD R, A
.db I_LD, 'l', 0xb, 0, 0b01110000 , 0 ; LD (HL), r
.db I_LD, 0xb, 'l', 3, 0b01000110 , 0 ; LD r, (HL)
.db I_LD, 'l', 'n', 0, 0x36 , 0 ; LD (HL), n
.db I_LD, 0xb, 'n', 3, 0b00000110 , 0 ; LD r, n
.db I_LD, 0xb, 0xb, 0x20 \ .dw handleLDrr ; LD r, r'
.db I_LD, 0x3, 'N', 4, 0b00000001 , 0 ; LD dd, nn
.db I_LD, 'X', 'N', 0, 0xdd, 0x21 ; LD IX, NN
.db I_LD, 'Y', 'N', 0, 0xfd, 0x21 ; LD IY, NN
.db I_LD, 'M', 'A', 0, 0x32 , 0 ; LD (NN), A
.db I_LD, 'A', 'M', 0, 0x3a , 0 ; LD A, (NN)
.db I_LD, 'M', 'h', 0, 0x22 , 0 ; LD (NN), HL
.db I_LD, 'h', 'M', 0, 0x2a , 0 ; LD HL, (NN)
.db I_LD, 'M', 'X', 0, 0xdd, 0x22 ; LD (NN), IX
.db I_LD, 'X', 'M', 0, 0xdd, 0x2a ; LD IX, (NN)
.db I_LD, 'M', 'Y', 0, 0xfd, 0x22 ; LD (NN), IY
.db I_LD, 'Y', 'M', 0, 0xfd, 0x2a ; LD IY, (NN)
.db I_LD, 'M', 0x3, 0x44, 0xed, 0b01000011 ; LD (NN), dd
.db I_LD, 0x3, 'M', 0x44, 0xed, 0b01001011 ; LD dd, (NN)
.db I_LD, 'x', 'n', 0x20 \ .dw handleLDIXn ; LD (IX+d), n
.db I_LD, 'y', 'n', 0x20 \ .dw handleLDIYn ; LD (IY+d), n
.db I_LD, 'x', 0xb, 0x20 \ .dw handleLDIXr ; LD (IX+d), r
.db I_LD, 'y', 0xb, 0x20 \ .dw handleLDIYr ; LD (IY+d), r
.db I_LD, 0xb, 'x', 0x20 \ .dw handleLDrIX ; LD r, (IX+d)
.db I_LD, 0xb, 'y', 0x20 \ .dw handleLDrIY ; LD r, (IY+d)
.db I_LDD, 0, 0, 0, 0xed, 0xa8 ; LDD
.db I_LDDR,0, 0, 0, 0xed, 0xb8 ; LDDR
.db I_LDI, 0, 0, 0, 0xed, 0xa0 ; LDI
.db I_LDIR,0, 0, 0, 0xed, 0xb0 ; LDIR
.db I_NEG, 0, 0, 0, 0xed, 0x44 ; NEG
.db I_NOP, 0, 0, 0, 0x00 , 0 ; NOP
.db I_OR, 'l', 0, 0, 0xb6 , 0 ; OR (HL)
.db I_OR, 0xb, 0, 0, 0b10110000 , 0 ; OR r
.db I_OR, 'n', 0, 0, 0xf6 , 0 ; OR n
.db I_OR, 'x', 0, 0, 0xdd, 0xb6 ; OR (IX+d)
.db I_OR, 'y', 0, 0, 0xfd, 0xb6 ; OR (IY+d)
.db I_OTDR,0, 0, 0, 0xed, 0xbb ; OTDR
.db I_OTIR,0, 0, 0, 0xed, 0xb3 ; OTIR
.db I_OUT, 'm', 'A', 0, 0xd3 , 0 ; OUT (n), A
.db I_OUT, 'k', 0xb, 0x43, 0xed, 0b01000001 ; OUT (C), r
.db I_POP, 'X', 0, 0, 0xdd, 0xe1 ; POP IX
.db I_POP, 'Y', 0, 0, 0xfd, 0xe1 ; POP IY
.db I_POP, 0x1, 0, 4, 0b11000001 , 0 ; POP qq
.db I_PUSH,'X', 0, 0, 0xdd, 0xe5 ; PUSH IX
.db I_PUSH,'Y', 0, 0, 0xfd, 0xe5 ; PUSH IY
.db I_PUSH,0x1, 0, 4, 0b11000101 , 0 ; PUSH qq
.db I_RES, 'n', 'l', 0x20 \ .dw handleRESHL ; RES b, (HL)
.db I_RES, 'n', 'x', 0x20 \ .dw handleRESIX ; RES b, (IX+d)
.db I_RES, 'n', 'y', 0x20 \ .dw handleRESIY ; RES b, (IY+d)
.db I_RES, 'n', 0xb, 0x20 \ .dw handleRESR ; RES b, r
.db I_RET, 0, 0, 0, 0xc9 , 0 ; RET
.db I_RET, 0xa, 0, 3, 0b11000000 , 0 ; RET cc
.db I_RETI,0, 0, 0, 0xed, 0x4d ; RETI
.db I_RETN,0, 0, 0, 0xed, 0x45 ; RETN
.db I_RL, 0xb, 0,0x40, 0xcb, 0b00010000 ; RL r
.db I_RLA, 0, 0, 0, 0x17 , 0 ; RLA
.db I_RLC, 0xb, 0,0x40, 0xcb, 0b00000000 ; RLC r
.db I_RLCA,0, 0, 0, 0x07 , 0 ; RLCA
.db I_RR, 0xb, 0,0x40, 0xcb, 0b00011000 ; RR r
.db I_RRA, 0, 0, 0, 0x1f , 0 ; RRA
.db I_RRC, 0xb, 0,0x40, 0xcb, 0b00001000 ; RRC r
.db I_RRCA,0, 0, 0, 0x0f , 0 ; RRCA
.db I_SBC, 'A', 'l', 0, 0x9e , 0 ; SBC A, (HL)
.db I_SBC, 'A', 0xb, 0, 0b10011000 , 0 ; SBC A, r
.db I_SBC,'h',0x3,0x44, 0xed, 0b01000010 ; SBC HL, ss
.db I_SCF, 0, 0, 0, 0x37 , 0 ; SCF
.db I_SET, 'n', 'l', 0x20 \ .dw handleSETHL ; SET b, (HL)
.db I_SET, 'n', 'x', 0x20 \ .dw handleSETIX ; SET b, (IX+d)
.db I_SET, 'n', 'y', 0x20 \ .dw handleSETIY ; SET b, (IY+d)
.db I_SET, 'n', 0xb, 0x20 \ .dw handleSETR ; SET b, r
.db I_SLA, 0xb, 0,0x40, 0xcb, 0b00100000 ; SLA r
.db I_SRL, 0xb, 0,0x40, 0xcb, 0b00111000 ; SRL r
.db I_SUB, 'l', 0, 0, 0x96 , 0 ; SUB (HL)
.db I_SUB, 0xb, 0, 0, 0b10010000 , 0 ; SUB r
.db I_SUB, 'n', 0, 0, 0xd6 , 0 ; SUB n
.db I_XOR, 'l', 0, 0, 0xae , 0 ; XOR (HL)
.db I_XOR, 0xb, 0, 0, 0b10101000 , 0 ; XOR r
.db I_XOR, 'n', 0, 0, 0xee , 0 ; XOR n
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