mirror of
https://github.com/fadden/6502bench.git
synced 2026-04-27 03:17:45 +00:00
Andy McFadden
459cde40c4
Most assemblers treat '<' and '>' as byte-select operators. Merlin 32 treats them as shift operators, making '<' effectively a no-op. A mask is applied based on the length implied by the opcode or pseudo-op, e.g. "DFB <FOO" will mask off the high bits. This is problematic for instructions like "LDA <FOO", where the choice between absolute and DP addressing depends on the value of "<FOO". If FOO is >= $100, the lack of masking will cause it be treated as absolute. There is currently no other mechanism to force the use of a direct-page opcode. The only recourse is to append "&$ff" to the operand, so the assembler knows that it can be handled as a DP op. The code generator has been updated to add "&$ff" where needed, based on the label's value. Unfortunately the assembler doesn't accept this for certain specific addressing modes; this appears to be a bug. The relevant test cases (2003x-labels-and-symbols) have been updated to exercise these situations. The current test projects side-step the failing assembler behavior by using a DP label instead. These should be changed to correctly exercise the full behavior, with the code generator outputting the instructions as raw hex values to work around bugs. There are some deliberately broken things (like a duplicate label) in the 20030 case that were copied into the 20032 case when it was created. For ease of editing these have been removed from 20032. (issue #170)
116 lines
3.0 KiB
ArmAsm
116 lines
3.0 KiB
ArmAsm
;Project was edited to add a label in the middle of a dense hex region, and add
|
|
;a duplicate label.
|
|
.setcpu "6502"
|
|
BMI1 = $30 ;opcode mnemonic
|
|
zip = $cd
|
|
absl = $1029
|
|
absh = $feed
|
|
|
|
plataddr = $3000 ;address only in platform file
|
|
projalsa = $3200 ;same val as projalso
|
|
|
|
.org $2345
|
|
start: lda #zip
|
|
lda #zip+16
|
|
lda #zip-192
|
|
lda #<absh
|
|
lda #>absh
|
|
lda #<absh-192
|
|
lda #>absh+1
|
|
lda #<absl
|
|
lda #>absl
|
|
lda #<absl+192
|
|
lda #>absl-1
|
|
lda #<start
|
|
lda #>start
|
|
lda zip+1
|
|
lda a:zip+1
|
|
lda absh-1
|
|
lda absh+1
|
|
lda start+1
|
|
lda start-1
|
|
jmp @L23A3
|
|
|
|
.byte zip
|
|
.byte <absh
|
|
.byte >absh
|
|
.byte <start
|
|
.byte >start
|
|
.word zip
|
|
.word absl
|
|
.word absl >> 8
|
|
.word absl-$1000
|
|
.word absl >> 8 -16
|
|
.word absh
|
|
.word absh >> 8
|
|
.word absh-$f000
|
|
.word absh >> 8 +16
|
|
.word start
|
|
.word start >> 8
|
|
.word start+1
|
|
.word start >> 8
|
|
.dbyt absh
|
|
.faraddr zip
|
|
.faraddr absh
|
|
.faraddr absh >> 8
|
|
.faraddr start
|
|
.faraddr start >> 8
|
|
|
|
@L23A3: jmp @L1000_1
|
|
|
|
.org $1000
|
|
@L1000_1: nop
|
|
@L1000: nop
|
|
@L1000_0: nop
|
|
@l1000: lda plataddr
|
|
lda $3100
|
|
lda projalsa
|
|
lda $3300
|
|
jmp calls
|
|
|
|
nop
|
|
targ: nop
|
|
nop
|
|
L1015: jsr targ-1
|
|
jsr targ
|
|
jsr targ+1
|
|
L101E: jmp targ-1
|
|
|
|
L1021: jmp targ
|
|
|
|
L1024: jmp targ+1
|
|
|
|
L1027: jmp targ-1
|
|
|
|
L102A: jmp targ
|
|
|
|
L102D: jmp targ+1
|
|
|
|
calls: jsr L1015
|
|
jsr L101E
|
|
jsr L1021
|
|
jsr L1024
|
|
jsr L1027
|
|
jsr L102A
|
|
jsr L102D
|
|
jmp L1160
|
|
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f ;bulky
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f
|
|
.byte $80,$81,$82,$83,$84,$85,$86,$87,$88,$89,$8a,$8b,$8c,$8d,$8e,$8f
|
|
.byte "This is a long string. Put a label and comment on it to confir" ;stringy
|
|
.byte "m that the label and comment only appear on the first line. T"
|
|
.byte "he quick brown fox jumps over the lazy dogs."
|
|
|
|
L1160: adc #BMI1
|
|
lda <targ-1
|
|
lda <targ+1
|
|
lda <targ-1,x
|
|
lda (<targ+4),y
|
|
rts
|
|
|