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SixtyPical/doc/Emitting.markdown
2014-04-03 13:32:06 +01:00

4.2 KiB

Emitting Ophis from SixtyPical Programs

-> Tests for functionality "Emit ASM for SixtyPical program"

-> Functionality "Emit ASM for SixtyPical program" is implemented by
-> shell command "bin/sixtypical emit %(test-file)"

| reserve word vword
| reserve byte vbyte
| assign byte table table 1024
| routine main {
|    lda #4
|    ldx #0
|    ldy #$FF
|    lda vbyte
|    lda table, x
|    lda table, y
|    lda (vword), y
|    lda <vword
|    lda >vword
|    inc vbyte
|    tax
|    inx
|    dex
|    stx vbyte
|    tay
|    iny
|    dey
|    sty vbyte
|    cmp vbyte
|    cmp #30
|    cmp <vword
|    cmp >vword
|    ldx vbyte
|    cpx vbyte
|    cpx #31
|    txa
|    ldy vbyte
|    cpy vbyte
|    cpy #32
|    tya
|    sta vbyte
|    sta table, x
|    sta table, y
|    sta (vword), y
|    sta <vword
|    sta >vword
|    dec vbyte
|    clc
|    cld
|    clv
|    sec
|    sed
|    adc #8
|    adc vbyte
|    and #8
|    and vbyte
|    sbc #8
|    sbc vbyte
|    ora #8
|    ora vbyte
| }
= main:
=   lda #4
=   ldx #0
=   ldy #255
=   lda vbyte
=   lda table, x
=   lda table, y
=   lda (vword), y
=   lda vword
=   lda vword+1
=   inc vbyte
=   tax
=   inx
=   dex
=   stx vbyte
=   tay
=   iny
=   dey
=   sty vbyte
=   cmp vbyte
=   cmp #30
=   cmp vword
=   cmp vword+1
=   ldx vbyte
=   cpx vbyte
=   cpx #31
=   txa
=   ldy vbyte
=   cpy vbyte
=   cpy #32
=   tya
=   sta vbyte
=   sta table, x
=   sta table, y
=   sta (vword), y
=   sta vword
=   sta vword+1
=   dec vbyte
=   clc
=   cld
=   clv
=   sec
=   sed
=   adc #8
=   adc vbyte
=   and #8
=   and vbyte
=   sbc #8
=   sbc vbyte
=   ora #8
=   ora vbyte
=   rts
= 
= vword: .word 0
= vbyte: .byte 0
= .alias table 1024

| assign byte screen $0400
| routine main {
|    lda screen
|    cmp screen
|    if beq {
|        tax
|    } else {
|        tay
|    }
|    sta screen
| }
= main:
=   lda screen
=   cmp screen
=   BEQ _label_1
=   tay
=   jmp _past_1
= _label_1:
=   tax
= _past_1:
=   sta screen
=   rts
= 
= .alias screen 1024

| assign byte screen 1024
| reserve byte zero
| routine main {
|    ldy zero
|    repeat bne {
|       inc screen
|       dey
|       cpy zero
|    }
|    sty screen
| }
= main:
=   ldy zero
=   
= _repeat_1:
=   inc screen
=   dey
=   cpy zero
=   BNE _repeat_1
=   sty screen
=   rts
= 
= .alias screen 1024
= zero: .byte 0

Nested ifs.

| routine main {
|   if beq {
|     if bcc {
|       lda #0
|     } else {
|       if bvs {
|         lda #1
|       } else {
|         lda #2
|       }
|     }
|   } else {
|     lda #3
|   }
| }
= main:
=   BEQ _label_3
=   lda #3
=   jmp _past_3
= _label_3:
=   BCC _label_2
=   BVS _label_1
=   lda #2
=   jmp _past_1
= _label_1:
=   lda #1
= _past_1:
=   jmp _past_2
= _label_2:
=   lda #0
= _past_2:
= _past_3:
=   rts

Installing an interrupt handler (at the Kernal level, i.e. with CINV)

| assign byte screen 1024
| assign vector cinv 788
| reserve vector save_cinv
| 
| routine main {
|   sei {
|     copy vector cinv to save_cinv
|     copy routine our_cinv to cinv
|   }
| }
| 
| routine our_cinv {
|   inc screen
|   jmp save_cinv
| }
= main:
=   sei
=   lda cinv
=   sta save_cinv
=   lda cinv+1
=   sta save_cinv+1
=   lda #<our_cinv
=   sta cinv
=   lda #>our_cinv
=   sta cinv+1
=   cli
=   rts
= 
= our_cinv:
=   inc screen
=   jmp (save_cinv)
=   rts
= 
= .alias screen 1024
= .alias cinv 788
= save_cinv: .word 0