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6502bench/SourceGen/SGTestData/Source/20052-branches-and-banks.S
Andy McFadden fdd2bcf847 Fix some 65816 code generation issues
Two basic problems:

(1) cc65, being a one-pass assembler, can't tell if a forward-referenced
label is 16-bit or 24-bit.  If the operand is potentially ambiguous,
such as "LDA label", we need to add an operand width disambiguator.
(The existing tests managed to only do backward references.)

(2) 64tass wants the labels on JMP/JSR absolute operands to have 24-bit
values that match the current program bank.  This is the opposite of
cc65, which requires 16-bit values.  We need to distinguish PBR vs.
DBR instructions (i.e. "LDA abs" vs. "JMP abs") and handle them
differently when formatting for "Common".

Merlin32 doesn't care, and ACME doesn't work at all, so neither of
those needed updating.

The 20052-branches-and-banks test was expanded to cover the problematic
cases.
2020-07-01 17:59:12 -07:00

134 lines
4.1 KiB
ArmAsm

; Copyright 2018 faddenSoft. All Rights Reserved.
; See the LICENSE.txt file for distribution terms (Apache 2.0).
;
; Assembler: cc65
;
; For the 65816 we want to exercise some additional things.
.setcpu "65816"
symlong = $123456
.org $1000
clc
xce
sep #$30
jml bank44
lodat: .byte $00,$01,$02 ;EDIT: set label
.org $440000
bank44: cmp f:bank44
low44: lda bank44
lda a:bank44 & $ffff
lda z:bank44 & $ffff ;DP ref, should resolve to "zero"
bmi low44
per low44-$40
bne low44-$40 ;branch to high44
brl bank44-$40 ;branch to late44
dat44: ;EDIT: set label
.addr dat44 ;EDIT: format as 16-bit Address
.faraddr dat44 ;EDIT: format as 24-bit Address
.org $44ffc0
late44: cmp f:late44
high44: beq cont44 ;EDIT: set label
bmi late44+$44 ;branch to low44
brl late44+$44 ;branch to low44
cont44: jml twok
.org $2000
twok: bit twok
pea dat44 & $ffff ;EDIT: set symbol=dat44
pea dat44 >> 16 ;EDIT: set symbol=dat44
bne skip
jmp [lodat]
skip: nop
j1: jsr j2 ;EDIT: set symbol=j2 for all, confirm auto-labels vanish
j2: jsr j3 ;EDIT: set label
j3: jsr j1
jsl symlong
jml bank54
.org $543210
bank54: cmp f:bank54
bra nxt54a
backchk:
nop ;EDIT: set label
nop
rts
backval:
.word backchk & $ffff
.byte bank54 >> 16
nxt54a:
; Test forward/backward refs. In cc65 this makes a difference because it's
; a one-pass assembler.
lda f:backchk ;EDIT: use symbol
lda f:fwdchk ;EDIT: use symbol
lda f:backchk ;EDIT: use hex
lda f:fwdchk ;EDIT: use hex
lda a:backchk & $ffff + 1 ;EDIT: use symbol
lda a:backchk & $ffff - 1 ;EDIT: use symbol
lda a:fwdchk & $ffff + 1 ;EDIT: use symbol
lda a:fwdchk & $ffff - 1 ;EDIT: use symbol
; Test non-bank-0 JSRs. The behavior varies significantly by assembler. The
; trick is that the high byte comes from the 'K' register. cc65 wants you
; to remove it for a 16-bit JSR (or fails because the operand is too big),
; 64tass wants you to keep it in place (or fails because you're trying to
; jump to the wrong bank), and Merlin32 doesn't care.
nop
jsr backchk & $ffff
jsr backchk & $ffff + 1 ;EDIT: set to "backchk"
jsr backchk & $ffff + 2 ;leave in hex
jsr fwdchk & $ffff
jsr fwdchk & $ffff + 1 ;EDIT: set to "fwdchk"
jsr fwdchk & $ffff + 2 ;leave in hex
nop
ldx #$00
jsr (backval & $ffff,X)
jsr (fwdval & $ffff,X)
jsr jmp1b & $ffff
jsr jmp1f & $ffff
jsr jmp2b & $ffff
jsr jmp2f & $ffff
jsr jmp3b & $ffff
jsr jmp3f & $ffff
bra nxt54b
; Fun fact: "JMP (addr)" and "JML [addr]" always load the indirect value
; from zero page. They do *not* use B or K. The (addr,X) mode uses the
; program bank (K). According to Eyes & Lichty, this is because the
; non-indexed form assumes you're jumping through a variable, while the
; indexed form assumes you've got an address table in your code. (Think
; how they would be used in ROM.)
jmp2b: jmp (backval & $ffff,X)
jmp2f: jmp (fwdval & $ffff,X)
jmp1b: jmp (lodat)
jmp1f: jmp (lodat)
jmp3b: jmp [lodat]
jmp3f: jmp [lodat]
fwdval:
.word fwdchk & $ffff
.byte bank54 >> 16
fwdchk:
nop ;EDIT: set label
nop
rts
nxt54b:
jsr skip ;EDIT: set to "skip" label
rtl