SixtyPical Compilation
This is a test suite, written in Falderal format, for compiling SixtyPical to 6502 machine code.
-> Tests for functionality "Compile SixtyPical program"
Null program.
| define main routine
| {
| }
= $080D RTS
nop program.
| define main routine
| {
| nop
| }
= $080D NOP
= $080E RTS
Rudimentary program.
| define main routine
| inputs a
| outputs a
| trashes c, z, n, v
| {
| st off, c
| add a, 4
| }
= $080D CLC
= $080E ADC #$04
= $0810 RTS
Call extern.
| define chrout routine
| inputs a
| trashes a
| @ 65490
|
| define main routine
| inputs a
| trashes a, z, n
| {
| ld a, 65
| call chrout
| ld a, 0
| }
= $080D LDA #$41
= $080F JSR $FFD2
= $0812 LDA #$00
= $0814 RTS
Call defined routine.
| define foo routine
| outputs a, x, y
| trashes z, n
| {
| ld a, 0
| ld x, 0
| ld y, 0
| }
|
| define main routine
| trashes a, x, y, z, n
| {
| call foo
| ld a, 1
| }
= $080D JSR $0813
= $0810 LDA #$01
= $0812 RTS
= $0813 LDA #$00
= $0815 LDX #$00
= $0817 LDY #$00
= $0819 RTS
Tail call is optimized into a jump.
| define foo routine
| outputs a, x, y
| trashes z, n
| {
| ld a, 0
| ld x, 0
| ld y, 0
| }
|
| define main routine
| trashes a, x, y, z, n
| {
| ld a, 1
| call foo
| }
= $080D LDA #$01
= $080F JMP $0812
= $0812 LDA #$00
= $0814 LDX #$00
= $0816 LDY #$00
= $0818 RTS
Access a defined memory location.
| byte foo
|
| define main routine
| trashes a, y, z, n, foo
| {
| ld y, 0
| st y, foo
| ld a, foo
| }
= $080D LDY #$00
= $080F STY $0816
= $0812 LDA $0816
= $0815 RTS
Memory location with explicit address.
| byte screen @ 1024
|
| define main routine
| trashes a, z, n, screen
| {
| ld a, 100
| st a, screen
| }
= $080D LDA #$64
= $080F STA $0400
= $0812 RTS
Accesses to memory locations in zero-page with ld and st
and and, or, and xor use zero-page addressing.
| byte zp @ $00
| byte screen @ 100
|
| define main routine
| inputs screen, zp
| outputs screen, zp
| trashes a, z, n
| {
| ld a, screen
| st a, screen
| ld a, zp
| st a, zp
| and a, zp
| or a, zp
| xor a, zp
| }
= $080D LDA $64
= $080F STA $64
= $0811 LDA $00
= $0813 STA $00
= $0815 AND $00
= $0817 ORA $00
= $0819 EOR $00
= $081B RTS
Memory location with initial value.
| byte lives : 3
|
| define main routine
| inputs lives
| trashes a, z, n
| {
| ld a, lives
| }
= $080D LDA $0811
= $0810 RTS
= $0811 .byte $03
Word memory locations with explicit address, initial value.
| word w1 @ 60001
| word w2 : 3003
|
| define main routine
| inputs w1
| outputs w2
| trashes a, z, n
| {
| copy w1, w2
| }
= $080D LDA $EA61
= $0810 STA $081A
= $0813 LDA $EA62
= $0816 STA $081B
= $0819 RTS
= $081A .byte $BB
= $081B .byte $0B
Initialized byte table, initialized with ASCII string. Bytes allocated, but beyond the string, are 0's.
| byte table[8] message : "WHAT?"
|
| define main routine
| inputs message
| outputs x, a, z, n
| {
| ld x, 0
| ld a, message + x
| }
= $080D LDX #$00
= $080F LDA $0813,X
= $0812 RTS
= $0813 .byte $57
= $0814 PHA
= $0815 EOR ($54,X)
= $0817 .byte $3F
= $0818 BRK
= $0819 BRK
= $081A BRK
Initialized byte table, initialized with list of byte values.
| byte table[8] message : 255, 0, 129, 128, 127
|
| define main routine
| inputs message
| outputs x, a, z, n
| {
| ld x, 0
| ld a, message + x
| }
= $080D LDX #$00
= $080F LDA $0813,X
= $0812 RTS
= $0813 .byte $FF
= $0814 BRK
= $0815 STA ($80,X)
= $0817 .byte $7F
= $0818 BRK
= $0819 BRK
= $081A BRK
Initialized word table, initialized with list of word values.
| word table[4] message : 65535, 0, 127, 127
|
| define main routine
| {
| }
= $080D RTS
= $080E .byte $FF
= $080F .byte $FF
= $0810 BRK
= $0811 BRK
= $0812 .byte $7F
= $0813 BRK
= $0814 .byte $7F
= $0815 BRK
Some instructions.
| byte foo
|
| define main routine
| trashes a, x, y, z, n, c, v, foo
| {
| ld a, 0
| ld x, 0
| ld y, 0
| st a, foo
| st x, foo
| st y, foo
| st on, c
| st off, c
| add a, 1
| add a, foo
| sub a, 1
| sub a, foo
| inc foo
| inc x
| inc y
| dec foo
| dec x
| dec y
| and a, 255
| and a, foo
| or a, 255
| or a, foo
| xor a, 255
| xor a, foo
| cmp a, 1
| cmp a, foo
| cmp x, 1
| cmp x, foo
| cmp y, 1
| cmp y, foo
| shl a
| shr a
| shl foo
| shr foo
| }
= $080D LDA #$00
= $080F LDX #$00
= $0811 LDY #$00
= $0813 STA $0859
= $0816 STX $0859
= $0819 STY $0859
= $081C SEC
= $081D CLC
= $081E ADC #$01
= $0820 ADC $0859
= $0823 SBC #$01
= $0825 SBC $0859
= $0828 INC $0859
= $082B INX
= $082C INY
= $082D DEC $0859
= $0830 DEX
= $0831 DEY
= $0832 AND #$FF
= $0834 AND $0859
= $0837 ORA #$FF
= $0839 ORA $0859
= $083C EOR #$FF
= $083E EOR $0859
= $0841 CMP #$01
= $0843 CMP $0859
= $0846 CPX #$01
= $0848 CPX $0859
= $084B CPY #$01
= $084D CPY $0859
= $0850 ROL A
= $0851 ROR A
= $0852 ROL $0859
= $0855 ROR $0859
= $0858 RTS
Some instructions on tables. (1/3)
| byte table[256] many
|
| define main routine
| inputs many
| outputs many
| trashes a, x, c, n, z, v
| {
| ld x, 0
| ld a, 0
| st off, c
| add a, many + x
| sub a, many + x
| cmp a, many + x
| }
= $080D LDX #$00
= $080F LDA #$00
= $0811 CLC
= $0812 ADC $081C,X
= $0815 SBC $081C,X
= $0818 CMP $081C,X
= $081B RTS
Some instructions on tables. (2/3)
| byte table[256] many
|
| define main routine
| inputs many
| outputs many
| trashes a, x, c, n, z
| {
| ld x, 0
| ld a, 0
| and a, many + x
| or a, many + x
| xor a, many + x
| }
= $080D LDX #$00
= $080F LDA #$00
= $0811 AND $081B,X
= $0814 ORA $081B,X
= $0817 EOR $081B,X
= $081A RTS
Some instructions on tables. (3/3)
| byte table[256] many
|
| define main routine
| inputs many
| outputs many
| trashes a, x, c, n, z
| {
| ld x, 0
| ld a, 0
| st off, c
| shl many + x
| shr many + x
| inc many + x
| dec many + x
| }
= $080D LDX #$00
= $080F LDA #$00
= $0811 CLC
= $0812 ROL $081F,X
= $0815 ROR $081F,X
= $0818 INC $081F,X
= $081B DEC $081F,X
= $081E RTS
Using a constant offset, you can read and write entries in the table beyond the 256th.
| byte one
| byte table[1024] many
|
| define main routine
| inputs many
| outputs many
| trashes a, x, n, z
| {
| ld x, 0
| ld a, many + x
| st a, many + x
| ld a, many + 999 + x
| st a, many + 1000 + x
| }
= $080D LDX #$00
= $080F LDA $081D,X
= $0812 STA $081D,X
= $0815 LDA $0C04,X
= $0818 STA $0C05,X
= $081B RTS
Instructions on tables, with constant offsets.
| byte table[256] many
|
| define main routine
| inputs many
| outputs many
| trashes a, x, c, n, z, v
| {
| ld x, 0
| ld a, 0
| st off, c
| add a, many + 1 + x
| sub a, many + 2 + x
| cmp a, many + 3 + x
| and a, many + 4 + x
| or a, many + 5 + x
| xor a, many + 6 + x
| shl many + 7 + x
| shr many + 8 + x
| inc many + 9 + x
| dec many + 10 + x
| }
= $080D LDX #$00
= $080F LDA #$00
= $0811 CLC
= $0812 ADC $0832,X
= $0815 SBC $0833,X
= $0818 CMP $0834,X
= $081B AND $0835,X
= $081E ORA $0836,X
= $0821 EOR $0837,X
= $0824 ROL $0838,X
= $0827 ROR $0839,X
= $082A INC $083A,X
= $082D DEC $083B,X
= $0830 RTS
Compiling 16-bit cmp.
| word za @ 60001
| word zb : 3003
|
| define main routine
| inputs za, zb
| trashes a, z, c, n
| {
| cmp za, zb
| cmp za, 4000
| }
= $080D LDA $EA61
= $0810 CMP $0828
= $0813 BNE $081B
= $0815 LDA $EA62
= $0818 CMP $0829
= $081B LDA $EA61
= $081E CMP #$A0
= $0820 BNE $0827
= $0822 LDA $EA62
= $0825 CMP #$0F
= $0827 RTS
= $0828 .byte $BB
= $0829 .byte $0B
Compiling if.
| define main routine
| trashes a, x, y, z, n, c, v
| {
| ld a, 0
| if z {
| ld y, 1
| } else {
| ld y, 2
| }
| }
= $080D LDA #$00
= $080F BNE $0816
= $0811 LDY #$01
= $0813 JMP $0818
= $0816 LDY #$02
= $0818 RTS
Compiling if not.
| define main routine
| trashes a, x, y, z, n, c, v
| {
| ld a, 0
| if not z {
| ld y, 1
| } else {
| ld y, 2
| }
| }
= $080D LDA #$00
= $080F BEQ $0816
= $0811 LDY #$01
= $0813 JMP $0818
= $0816 LDY #$02
= $0818 RTS
Compiling if without else.
| define main routine
| trashes a, x, y, z, n, c, v
| {
| ld a, 0
| ld y, 0
| if z {
| ld y, 1
| }
| }
= $080D LDA #$00
= $080F LDY #$00
= $0811 BNE $0815
= $0813 LDY #$01
= $0815 RTS
Compiling repeat ... until z.
| define main routine
| trashes a, y, z, n, c
| {
| ld y, 65
| repeat {
| ld a, y
| inc y
| cmp y, 91
| } until z
| }
= $080D LDY #$41
= $080F TYA
= $0810 INY
= $0811 CPY #$5B
= $0813 BNE $080F
= $0815 RTS
Compiling repeat ... until not z.
| define main routine
| trashes a, y, z, n, c
| {
| ld y, 65
| repeat {
| ld a, y
| inc y
| cmp y, 91
| } until not z
| }
= $080D LDY #$41
= $080F TYA
= $0810 INY
= $0811 CPY #$5B
= $0813 BEQ $080F
= $0815 RTS
Compiling repeat ... until n.
| define main routine
| trashes a, y, z, n, c
| {
| ld y, 65
| repeat {
| ld a, y
| dec y
| } until n
| }
= $080D LDY #$41
= $080F TYA
= $0810 DEY
= $0811 BPL $080F
= $0813 RTS
Compiling repeat ... until not n.
| define main routine
| trashes a, y, z, n, c
| {
| ld y, 199
| repeat {
| ld a, y
| inc y
| } until not n
| }
= $080D LDY #$C7
= $080F TYA
= $0810 INY
= $0811 BMI $080F
= $0813 RTS
Compiling repeat forever.
| define main routine
| trashes a, y, z, n, c
| {
| ld y, 65
| repeat {
| inc y
| } forever
| }
= $080D LDY #$41
= $080F INY
= $0810 JMP $080F
The body of repeat forever can be empty.
| define main routine
| {
| repeat {
| } forever
| }
= $080D JMP $080D
Compiling for ... up to.
| byte table[256] tab
|
| define main routine
| inputs tab
| trashes a, x, c, z, v, n
| {
| ld x, 0
| for x up to 15 {
| ld a, tab + x
| }
| }
= $080D LDX #$00
= $080F LDA $0818,X
= $0812 INX
= $0813 CPX #$10
= $0815 BNE $080F
= $0817 RTS
Compiling for ... down to.
| byte table[256] tab
|
| define main routine
| inputs tab
| trashes a, x, c, z, v, n
| {
| ld x, 15
| for x down to 0 {
| ld a, tab + x
| }
| }
= $080D LDX #$0F
= $080F LDA $0818,X
= $0812 DEX
= $0813 CPX #$FF
= $0815 BNE $080F
= $0817 RTS
Compiling save.
| define main routine
| inputs a
| outputs a
| trashes z, n
| {
| save a {
| save x {
| ld a, 0
| ld x, 1
| }
| }
| }
= $080D PHA
= $080E TXA
= $080F PHA
= $0810 LDA #$00
= $0812 LDX #$01
= $0814 PLA
= $0815 TAX
= $0816 PLA
= $0817 RTS
Compiling save with shortcut syntax.
| define main routine
| inputs a
| outputs a
| trashes z, n
| {
| save a, x {
| ld a, 0
| ld x, 1
| }
| }
= $080D PHA
= $080E TXA
= $080F PHA
= $0810 LDA #$00
= $0812 LDX #$01
= $0814 PLA
= $0815 TAX
= $0816 PLA
= $0817 RTS
Compiling save on a user-defined location.
| byte foo
| define main routine
| trashes a, z, n
| {
| save foo {
| ld a, 0
| st a, foo
| }
| }
= $080D LDA $081B
= $0810 PHA
= $0811 LDA #$00
= $0813 STA $081B
= $0816 PLA
= $0817 STA $081B
= $081A RTS
Indexed access.
| byte one
| byte table[256] many
|
| define main routine
| outputs many
| trashes a, x, n, z
| {
| ld x, 0
| ld a, 0
| st a, many + x
| ld a, many + x
| }
= $080D LDX #$00
= $080F LDA #$00
= $0811 STA $0819,X
= $0814 LDA $0819,X
= $0817 RTS
Byte tables take up, at most, 256 bytes in memory.
| byte table[256] tab1
| byte table[256] tab2
|
| define main routine
| inputs tab1
| outputs tab2
| trashes a, x, n, z
| {
| ld x, 0
| ld a, tab1 + x
| st a, tab2 + x
| }
= $080D LDX #$00
= $080F LDA $0816,X
= $0812 STA $0916,X
= $0815 RTS
Byte storage locations take up only 1 byte in memory.
| byte one
| byte two
|
| define main routine
| outputs one, two
| trashes a, x, n, z
| {
| ld a, 0
| st a, one
| st a, two
| }
= $080D LDA #$00
= $080F STA $0816
= $0812 STA $0817
= $0815 RTS
Copy byte to byte.
| byte bar
| byte baz
|
| define main routine
| inputs baz
| outputs bar
| trashes a, n, z
| {
| copy baz, bar
| }
= $080D LDA $0815
= $0810 STA $0814
= $0813 RTS
Copy word to word.
| word bar
| word baz
|
| define main routine
| inputs baz
| outputs bar
| trashes a, n, z
| {
| copy baz, bar
| }
= $080D LDA $081C
= $0810 STA $081A
= $0813 LDA $081D
= $0816 STA $081B
= $0819 RTS
Copy literal word to word.
| word bar
|
| define main routine
| outputs bar
| trashes a, n, z
| {
| copy 2000, bar
| }
= $080D LDA #$D0
= $080F STA $0818
= $0812 LDA #$07
= $0814 STA $0819
= $0817 RTS
You can also copy a literal word to a word table.
| word table[256] many
|
| define main routine
| inputs many
| outputs many
| trashes a, x, n, z
| {
| ld x, 0
| copy 9999, many + x
| }
= $080D LDX #$00
= $080F LDA #$0F
= $0811 STA $081A,X
= $0814 LDA #$27
= $0816 STA $091A,X
= $0819 RTS
Copy vector to vector.
| vector routine bar
| vector routine baz
|
| define main routine
| inputs baz
| outputs bar
| trashes a, n, z
| {
| copy baz, bar
| }
= $080D LDA $081C
= $0810 STA $081A
= $0813 LDA $081D
= $0816 STA $081B
= $0819 RTS
Copy routine to vector, inside an interrupts off block.
| vector routine
| inputs x
| outputs x
| trashes z, n
| bar
|
| define foo routine
| inputs x
| outputs x
| trashes z, n
| {
| inc x
| }
|
| define main routine
| outputs bar
| trashes a, n, z
| {
| with interrupts off {
| copy foo, bar
| }
| }
= $080D SEI
= $080E LDA #$1A
= $0810 STA $081C
= $0813 LDA #$08
= $0815 STA $081D
= $0818 CLI
= $0819 RTS
= $081A INX
= $081B RTS
Copy routine (by forward reference) to vector.
| vector routine
| inputs x
| outputs x
| trashes z, n
| bar
|
| define main routine
| outputs bar
| trashes a, n, z
| {
| copy foo, bar
| }
|
| define foo routine
| inputs x
| outputs x
| trashes z, n
| {
| inc x
| }
= $080D LDA #$18
= $080F STA $081A
= $0812 LDA #$08
= $0814 STA $081B
= $0817 RTS
= $0818 INX
= $0819 RTS
Copy byte to byte table and back, with both x and y as indexes,
plus constant offsets.
| byte one
| byte table[256] many
|
| define main routine
| inputs one, many
| outputs one, many
| trashes a, x, y, n, z
| {
| ld x, 0
| ld y, 0
| ld a, 77
| st a, many + x
| st a, many + y
| st a, many + 1 + x
| st a, many + 1 + y
| ld a, many + x
| ld a, many + y
| ld a, many + 8 + x
| ld a, many + 8 + y
| }
= $080D LDX #$00
= $080F LDY #$00
= $0811 LDA #$4D
= $0813 STA $082D,X
= $0816 STA $082D,Y
= $0819 STA $082E,X
= $081C STA $082E,Y
= $081F LDA $082D,X
= $0822 LDA $082D,Y
= $0825 LDA $0835,X
= $0828 LDA $0835,Y
= $082B RTS
Copy word to word table and back, with both x and y as indexes.
| word one
| word table[256] many
|
| define main routine
| inputs one, many
| outputs one, many
| trashes a, x, y, n, z
| {
| ld x, 0
| ld y, 0
| copy 777, one
| copy one, many + x
| copy one, many + y
| copy many + x, one
| copy many + y, one
| }
= $080D LDX #$00
= $080F LDY #$00
= $0811 LDA #$09
= $0813 STA $084C
= $0816 LDA #$03
= $0818 STA $084D
= $081B LDA $084C
= $081E STA $084E,X
= $0821 LDA $084D
= $0824 STA $094E,X
= $0827 LDA $084C
= $082A STA $084E,Y
= $082D LDA $084D
= $0830 STA $094E,Y
= $0833 LDA $084E,X
= $0836 STA $084C
= $0839 LDA $094E,X
= $083C STA $084D
= $083F LDA $084E,Y
= $0842 STA $084C
= $0845 LDA $094E,Y
= $0848 STA $084D
= $084B RTS
Copy word to word table and back, with constant offsets.
| word one
| word table[256] many
|
| define main routine
| inputs one, many
| outputs one, many
| trashes a, x, y, n, z
| {
| ld x, 0
| ld y, 0
| copy 777, one
| copy one, many + 1 + x
| copy one, many + 2 + y
| copy many + 3 + x, one
| copy many + 4 + y, one
| }
= $080D LDX #$00
= $080F LDY #$00
= $0811 LDA #$09
= $0813 STA $084C
= $0816 LDA #$03
= $0818 STA $084D
= $081B LDA $084C
= $081E STA $084F,X
= $0821 LDA $084D
= $0824 STA $094F,X
= $0827 LDA $084C
= $082A STA $0850,Y
= $082D LDA $084D
= $0830 STA $0950,Y
= $0833 LDA $0851,X
= $0836 STA $084C
= $0839 LDA $0951,X
= $083C STA $084D
= $083F LDA $0852,Y
= $0842 STA $084C
= $0845 LDA $0952,Y
= $0848 STA $084D
= $084B RTS
Indirect call. TODO: we don't need the final RTS here, omit it.
| vector routine
| outputs x
| trashes z, n
| foo
|
| define bar routine
| outputs x
| trashes z, n
| {
| ld x, 200
| }
|
| define main routine
| outputs x, foo
| trashes a, z, n
| {
| copy bar, foo
| call foo
| }
= $080D LDA #$1A
= $080F STA $0821
= $0812 LDA #$08
= $0814 STA $0822
= $0817 JMP $081D
= $081A LDX #$C8
= $081C RTS
= $081D JMP ($0821)
= $0820 RTS
Compiling goto. Note that no RTS is emitted after the JMP.
| define bar routine
| inputs y
| outputs x, y
| trashes z, n
| {
| ld x, 200
| }
|
| define main routine
| outputs x, y
| trashes a, z, n
| {
| ld y, 200
| goto bar
| }
= $080D LDY #$C8
= $080F JMP $0812
= $0812 LDX #$C8
= $0814 RTS
Vector tables
Copying to and from a vector table.
| vector routine
| outputs x
| trashes a, z, n
| one
| vector routine
| outputs x
| trashes a, z, n
| table[256] many
|
| define bar routine outputs x trashes a, z, n {
| ld x, 200
| }
|
| define main routine
| inputs one, many
| outputs one, many
| trashes a, x, n, z
| {
| ld x, 0
| copy bar, one
| copy bar, many + x
| copy one, many + x
| copy many + x, one
| call one
| }
= $080D LDX #$00
= $080F LDA #$3E
= $0811 STA $0845
= $0814 LDA #$08
= $0816 STA $0846
= $0819 LDA #$3E
= $081B STA $0847,X
= $081E LDA #$08
= $0820 STA $0947,X
= $0823 LDA $0845
= $0826 STA $0847,X
= $0829 LDA $0846
= $082C STA $0947,X
= $082F LDA $0847,X
= $0832 STA $0845
= $0835 LDA $0947,X
= $0838 STA $0846
= $083B JMP $0841
= $083E LDX #$C8
= $0840 RTS
= $0841 JMP ($0845)
= $0844 RTS
Copying to and from a vector table, with constant offsets.
| vector routine
| outputs x
| trashes a, z, n
| one
| vector routine
| outputs x
| trashes a, z, n
| table[256] many
|
| define bar routine outputs x trashes a, z, n {
| ld x, 200
| }
|
| define main routine
| inputs one, many
| outputs one, many
| trashes a, x, n, z
| {
| ld x, 0
| copy bar, one
| copy bar, many + 1 + x
| copy one, many + 2 + x
| copy many + 3 + x, one
| call one
| }
= $080D LDX #$00
= $080F LDA #$3E
= $0811 STA $0845
= $0814 LDA #$08
= $0816 STA $0846
= $0819 LDA #$3E
= $081B STA $0848,X
= $081E LDA #$08
= $0820 STA $0948,X
= $0823 LDA $0845
= $0826 STA $0849,X
= $0829 LDA $0846
= $082C STA $0949,X
= $082F LDA $084A,X
= $0832 STA $0845
= $0835 LDA $094A,X
= $0838 STA $0846
= $083B JMP $0841
= $083E LDX #$C8
= $0840 RTS
= $0841 JMP ($0845)
= $0844 RTS
add, sub
Various modes of add.
| byte lives
| byte extra
| word score
| word bonus
| define main routine
| inputs lives, score, extra, bonus
| outputs lives, score
| trashes a, x, y, c, z, v, n
| {
| ld a, 0
| ld x, 0
| ld y, 0
| st off, c
| add a, 7
| add a, lives
| add lives, 2
| add lives, extra
| add score, 1999
| add score, bonus
| }
= $080D LDA #$00
= $080F LDX #$00
= $0811 LDY #$00
= $0813 CLC
= $0814 ADC #$07
= $0816 ADC $084D
= $0819 LDA $084D
= $081C ADC #$02
= $081E STA $084D
= $0821 LDA $084D
= $0824 ADC $084E
= $0827 STA $084D
= $082A LDA $084F
= $082D ADC #$CF
= $082F STA $084F
= $0832 LDA $0850
= $0835 ADC #$07
= $0837 STA $0850
= $083A LDA $084F
= $083D ADC $0851
= $0840 STA $084F
= $0843 LDA $0850
= $0846 ADC $0852
= $0849 STA $0850
= $084C RTS
Various modes of sub.
| byte lives
| byte extra
| word score
| word bonus
| define main routine
| inputs lives, score, extra, bonus
| outputs lives, score
| trashes a, x, y, c, z, v, n
| {
| ld a, 0
| ld x, 0
| ld y, 0
| st on, c
| sub a, 7
| sub a, lives
| sub lives, 2
| sub lives, extra
| sub score, 1999
| sub score, bonus
| }
= $080D LDA #$00
= $080F LDX #$00
= $0811 LDY #$00
= $0813 SEC
= $0814 SBC #$07
= $0816 SBC $084D
= $0819 LDA $084D
= $081C SBC #$02
= $081E STA $084D
= $0821 LDA $084D
= $0824 SBC $084E
= $0827 STA $084D
= $082A LDA $084F
= $082D SBC #$CF
= $082F STA $084F
= $0832 LDA $0850
= $0835 SBC #$07
= $0837 STA $0850
= $083A LDA $084F
= $083D SBC $0851
= $0840 STA $084F
= $0843 LDA $0850
= $0846 SBC $0852
= $0849 STA $0850
= $084C RTS
word operations
Adding a constant word to a word memory location.
| word score
| define main routine
| inputs score
| outputs score
| trashes a, c, z, v, n
| {
| st off, c
| add score, 1999
| }
= $080D CLC
= $080E LDA $081F
= $0811 ADC #$CF
= $0813 STA $081F
= $0816 LDA $0820
= $0819 ADC #$07
= $081B STA $0820
= $081E RTS
Adding a word memory location to another word memory location.
| word score
| word delta
| define main routine
| inputs score, delta
| outputs score
| trashes a, c, z, v, n
| {
| st off, c
| add score, delta
| }
= $080D CLC
= $080E LDA $0821
= $0811 ADC $0823
= $0814 STA $0821
= $0817 LDA $0822
= $081A ADC $0824
= $081D STA $0822
= $0820 RTS
Subtracting a constant word from a word memory location.
| word score
| define main routine
| inputs score
| outputs score
| trashes a, c, z, v, n
| {
| st on, c
| sub score, 1999
| }
= $080D SEC
= $080E LDA $081F
= $0811 SBC #$CF
= $0813 STA $081F
= $0816 LDA $0820
= $0819 SBC #$07
= $081B STA $0820
= $081E RTS
Subtracting a word memory location from another word memory location.
| word score
| word delta
| define main routine
| inputs score, delta
| outputs score
| trashes a, c, z, v, n
| {
| st on, c
| sub score, delta
| }
= $080D SEC
= $080E LDA $0821
= $0811 SBC $0823
= $0814 STA $0821
= $0817 LDA $0822
= $081A SBC $0824
= $081D STA $0822
= $0820 RTS
Tables and Pointers
Associate pointer with table. Does nothing by itself.
| byte table[256] tab
| pointer ptr @ 254
|
| define main routine
| inputs tab
| outputs tab, y
| trashes a, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| }
| }
= $080D LDY #$00
= $080F RTS
Reset pointer to table.
| byte table[256] tab
| pointer ptr @ 254
|
| define main routine
| inputs tab
| outputs tab, y
| trashes a, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| reset ptr 0
| }
| }
= $080D LDY #$00
= $080F LDA #$18
= $0811 STA $FE
= $0813 LDA #$08
= $0815 STA $FF
= $0817 RTS
Write literal through a pointer.
| byte table[256] tab
| pointer ptr @ 254
|
| define main routine
| inputs tab
| outputs tab, y
| trashes a, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| reset ptr 0
| copy 123, [ptr] + y
| }
| }
= $080D LDY #$00
= $080F LDA #$1C
= $0811 STA $FE
= $0813 LDA #$08
= $0815 STA $FF
= $0817 LDA #$7B
= $0819 STA ($FE),Y
= $081B RTS
Write stored value through a pointer.
| byte table[256] tab
| pointer ptr @ 254
| byte foo
|
| define main routine
| inputs foo, tab
| outputs y, tab
| trashes a, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| reset ptr 0
| copy foo, [ptr] + y
| }
| }
= $080D LDY #$00
= $080F LDA #$1D
= $0811 STA $FE
= $0813 LDA #$08
= $0815 STA $FF
= $0817 LDA $091D
= $081A STA ($FE),Y
= $081C RTS
Read through a pointer, into a byte storage location, or the a register.
| byte table[256] tab
| pointer ptr @ 254
| byte foo
|
| define main routine
| inputs tab
| outputs y, foo
| trashes a, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| reset ptr 0
| copy [ptr] + y, foo
| ld a, [ptr] + y
| }
| }
= $080D LDY #$00
= $080F LDA #$1F
= $0811 STA $FE
= $0813 LDA #$08
= $0815 STA $FF
= $0817 LDA ($FE),Y
= $0819 STA $091F
= $081C LDA ($FE),Y
= $081E RTS
Multiple resets may occur inside the same block.
| byte table[256] tab @ 1024
| pointer ptr @ 254
| byte foo
|
| define main routine
| inputs tab
| outputs y, foo
| trashes a, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| reset ptr 16
| copy [ptr] + y, foo
| reset ptr 18
| ld a, [ptr] + y
| }
| }
= $080D LDY #$00
= $080F LDA #$10
= $0811 STA $FE
= $0813 LDA #$04
= $0815 STA $FF
= $0817 LDA ($FE),Y
= $0819 STA $0827
= $081C LDA #$12
= $081E STA $FE
= $0820 LDA #$04
= $0822 STA $FF
= $0824 LDA ($FE),Y
= $0826 RTS
Read and write through two pointers.
| byte table[256] tab
| pointer ptra @ 252
| pointer ptrb @ 254
|
| define main routine
| inputs tab
| outputs tab
| trashes a, y, z, n, ptra, ptrb
| {
| ld y, 0
| point ptra into tab {
| reset ptra 0
| point ptrb into tab {
| reset ptrb 0
| copy [ptra] + y, [ptrb] + y
| }
| }
| }
= $080D LDY #$00
= $080F LDA #$24
= $0811 STA $FC
= $0813 LDA #$08
= $0815 STA $FD
= $0817 LDA #$24
= $0819 STA $FE
= $081B LDA #$08
= $081D STA $FF
= $081F LDA ($FC),Y
= $0821 STA ($FE),Y
= $0823 RTS
Write the a register through a pointer.
| byte table[256] tab
| pointer ptr @ 254
| byte foo
|
| define main routine
| inputs tab
| outputs tab
| trashes a, y, z, n, ptr
| {
| ld y, 0
| point ptr into tab {
| reset ptr 0
| ld a, 255
| st a, [ptr] + y
| }
| }
= $080D LDY #$00
= $080F LDA #$1C
= $0811 STA $FE
= $0813 LDA #$08
= $0815 STA $FF
= $0817 LDA #$FF
= $0819 STA ($FE),Y
= $081B RTS
Add a word memory location, and a literal word, to a pointer, and then read through it. Note that this is not range-checked. (Yet.)
| byte table[256] tab
| pointer ptr @ 254
| byte foo
| word delta
|
| define main routine
| inputs tab
| outputs y, foo, delta
| trashes a, c, v, z, n, ptr
| {
| copy 619, delta
| ld y, 0
| st off, c
| point ptr into tab {
| reset ptr 0
| add ptr, delta
| add ptr, word 1
| copy [ptr] + y, foo
| }
| }
= $080D LDA #$6B
= $080F STA $0943
= $0812 LDA #$02
= $0814 STA $0944
= $0817 LDY #$00
= $0819 CLC
= $081A LDA #$42
= $081C STA $FE
= $081E LDA #$08
= $0820 STA $FF
= $0822 LDA $FE
= $0824 ADC $0943
= $0827 STA $FE
= $0829 LDA $FF
= $082B ADC $0944
= $082E STA $FF
= $0830 LDA $FE
= $0832 ADC #$01
= $0834 STA $FE
= $0836 LDA $FF
= $0838 ADC #$00
= $083A STA $FF
= $083C LDA ($FE),Y
= $083E STA $0942
= $0841 RTS
Trash
Trash does nothing except indicate that we do not care about the value anymore.
| define main routine
| inputs a
| outputs x
| trashes a, z, n
| {
| ld x, a
| ld a, 0
| trash a
| }
= $080D TAX
= $080E LDA #$00
= $0810 RTS
locals
Memory locations defined local static to a routine are allocated just the same as initialized global storage locations are.
| define foo routine
| inputs x
| outputs x
| trashes z, n
| static byte t : 255
| {
| st x, t
| inc t
| ld x, t
| }
|
| define main routine
| trashes a, x, z, n
| static byte t : 7
| {
| ld x, t
| call foo
| }
= $080D LDX $081E
= $0810 JMP $0813
= $0813 STX $081D
= $0816 INC $081D
= $0819 LDX $081D
= $081C RTS
= $081D .byte $FF
= $081E .byte $07
Memory locations defined local dynamic to a routine are allocated just the same as uninitialized global storage locations are.
| define foo routine
| inputs x
| outputs x
| trashes z, n
| local byte t
| {
| st x, t
| inc t
| ld x, t
| }
|
| define main routine
| trashes a, x, z, n
| local byte t
| {
| ld x, 0
| st x, t
| call foo
| }
= $080D LDX #$00
= $080F STX $0820
= $0812 JMP $0815
= $0815 STX $081F
= $0818 INC $081F
= $081B LDX $081F
= $081E RTS
Memory locations defined local dynamic to a routine are allocated just the same as uninitialized global storage locations are, even when declared with a fixed address.
| define foo routine
| inputs x
| outputs x
| trashes z, n
| local byte t @ 1024
| {
| st x, t
| inc t
| ld x, t
| }
|
| define main routine
| trashes a, x, z, n
| local byte t @ 1025
| {
| ld x, 0
| st x, t
| call foo
| }
= $080D LDX #$00
= $080F STX $0401
= $0812 JMP $0815
= $0815 STX $0400
= $0818 INC $0400
= $081B LDX $0400
= $081E RTS