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zasm: simplify code

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This commit is contained in:
Virgil Dupras 2019-04-21 14:23:24 -04:00
parent 93eb262083
commit 8594084b06
1 changed files with 14 additions and 20 deletions
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34
apps/zasm/zasm.asm
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@ -391,7 +391,8 @@ findInGroup:
; 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).
; 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 a, (hl)
@ -430,6 +431,12 @@ matchArg:
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 string at tokInstr. Sets Z flag if there's a
@ -535,11 +542,8 @@ handleBITR:
call handleBIT
ret nz ; error
; get group value
ld a, (curArg2)
ld h, 0xb
call findInGroup
ret nz ; error
push af ; push group value
ld a, (curArg2+1) ; group value
ld c, a
; write first upcode
ld a, 0xcb ; first upcode
ld (curUpcode), a
@ -549,8 +553,7 @@ handleBITR:
call rlaX
; Now we have group value in stack, bit value in A (properly shifted)
; and we want to OR them together
pop bc ; from push af earlier
or b ; Now we have our ORed value
or c ; Now we have our ORed value
or 0b01000000 ; and with the constant value for that byte...
; we're good!
ld (curUpcode+1), a
@ -609,11 +612,7 @@ handleLDIYr:
ld a, 0xfd
handleLDIXYr:
ld (curUpcode), a
; get group value
ld a, (curArg2)
ld h, 0xb
call findInGroup
ret nz ; error
ld a, (curArg2+1) ; group value
or 0b01110000 ; second upcode
ld (curUpcode+1), a
ld a, (curArg1+1) ; IXY displacement
@ -676,14 +675,9 @@ getUpcode:
ld hl, curArg1
.isGroup:
; A is a group, good, now let's get its value. HL is pointing to
; the argument. A little bit of stack gymnastic is necessary to put
; A into H and (HL) into A.
push af
; the argument. Our group value is at (HL+1).
inc hl
ld a, (hl)
pop hl ; from push af 2 lines above
call findInGroup ; we don't check for match, it's supposed to
; always match. Something is very wrong if it
; doesn't
; 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