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cc65/libsrc/cx16/vpoke.s
Greg King 9fa90e2265 Added VERA peek() and poke() to the cx16 library.
They simplify C programs' direct access to VERA's internal address space.
2019-10-24 05:15:42 -04:00

22 lines
562 B
ArmAsm

;
; 2019-10-22, Greg King
;
; void fastcall vpoke (unsigned char data, unsigned long addr);
; /* Put a byte into a location in VERA's internal address space.
; ** (addr is second instead of first for the sake of code efficiency.)
; */
;
.export _vpoke
.import vset, popa
.include "cx16.inc"
_vpoke: php ; (vset blocks interrupts)
jsr vset ; put VERA's address
jsr popa
sta VERA::DATA0 ; write data to VERA port zero
plp
rts