38 lines
1.8 KiB
PHP
38 lines
1.8 KiB
PHP
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
|
;; Macro to set a 16-bit address to the PPU_ADDR register (at $2006)
|
||
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
|
.macro PPU_SETADDR addr
|
||
|
|
bit PPU_STATUS ; Read from PPU_STATUS to reset the address latch
|
||
|
|
lda #>addr ; Fetch the hi-byte from 16-bit address
|
||
|
|
sta PPU_ADDR ; Store the hi-byte into PPU_ADDR $2006
|
||
|
|
lda #<addr ; Fetch the lo-byte from 16-bit address
|
||
|
|
sta PPU_ADDR ; Store the lo-byte into PPU_ADDR $2006
|
||
|
|
.endmacro
|
||
|
|
|
||
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
|
;; Macro to send a value to the PPU_DATA (at $2007)
|
||
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
|
.macro PPU_SETDATA val
|
||
|
|
lda val
|
||
|
|
sta PPU_DATA ; Send value to PPU register at $2007
|
||
|
|
.endmacro
|
||
|
|
|
||
|
|
|
||
|
|
.macro PUSH_REGS
|
||
|
|
pha ; Push A to the stack
|
||
|
|
txa ; transfer x to acc
|
||
|
|
pha ; Push X to the stack
|
||
|
|
tya ; transfer y to the acc
|
||
|
|
pha ; Push Y to the stack
|
||
|
|
php ; Push process status flags to the stack
|
||
|
|
.endmacro
|
||
|
|
|
||
|
|
.macro PULL_REGS
|
||
|
|
plp ; restore the status flags from the stack
|
||
|
|
pla ; restore the old value of Y from the stack into A
|
||
|
|
tay ; transfer
|
||
|
|
pla ; restore the old value of X from the stack into A
|
||
|
|
tax ; transfer
|
||
|
|
pla ; Pull a from the stack
|
||
|
|
.endmacro
|