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avra: small _parseArgs refactoring

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Take argspec pairs directly as an argument instead of taking a
pointer to an argspec pair.
This commit is contained in:
Virgil Dupras 2019-12-15 16:25:16 -05:00
parent 62eb5589c3
commit 14fbfa2967
1 changed files with 19 additions and 12 deletions
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31
apps/zasm/avr.asm
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@ -259,20 +259,23 @@ parseInstruction:
sla a ; A * 2
call addHL ; (HL) is our row
ld a, (hl)
push hl ; --> lvl 1
push hl \ pop ix ; IX is now our tblrow
ld hl, 0
or a
jr z, .noarg
and 0xf ; lower nibble
dec a ; argspec index is 1-based
ld hl, argSpecs
sla a ; A * 2
call addHL ; (HL) is argspec row
push hl \ pop ix
ld d, (hl)
inc hl
ld a, (hl)
ld h, d
ld l, a ; H and L contain specs now
call _parseArgs
.noarg:
pop ix ; <-- lvl 1, IX is now our tblrow
ret nz
.noarg:
; *** Step 3: place arguments in binary upcode and spit.
; (IX) is table row
; Parse arg values now in H and L
@ -417,7 +420,8 @@ parseInstruction:
.skip1:
and 0b111
ld c, a ; can't store in H now, (HL) is used
ld ix, argSpecs+4 ; 7, 0
ld h, 7
ld l, 0
call _parseArgs
ret nz
; ok, now we can
@ -443,7 +447,8 @@ parseInstruction:
; upcode becomes 0b111101
inc b
.rdBRBS:
ld ix, argSpecs+10 ; bit + k(7)
ld h, 'b'
ld l, 7
call _parseArgs
ret nz
; bit in H, k in L.
@ -484,8 +489,9 @@ argSpecs:
.db 'A', 'R' ; A(6) + Rr(5)
.db 'R', 'A' ; Rd(5) + A(6)
; Parse arguments from I/O according to specs in IX
; Puts the results in HL (which is not needed anymore after the parsing).
; Parse arguments from I/O according to specs in HL
; H for first spec, L for second spec
; Puts the results in HL
; First arg in H, second in L.
; This routine is not used in all cases, some ops don't fit this pattern well
; and thus parse their args themselves.
@ -494,20 +500,21 @@ _parseArgs:
; For the duration of the routine, our final value will be in DE, and
; then placed in HL at the end.
push de
ex de, hl ; argspecs now in DE
call readWord
jr nz, .end
ld a, (ix)
ld a, d
call .parse
jr nz, .end
ld d, a
ld a, (ix+1)
ld a, e
or a
jr z, .end ; no arg
call readComma
jr nz, .end
call readWord
jr nz, .end
ld a, (ix+1)
ld a, e
call .parse
jr nz, .end
; we're done with (HL) now