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cc65/libsrc/cx16/vpeek.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

20 lines
465 B
ArmAsm

;
; 2019-10-22, Greg King
;
; unsigned char fastcall vpeek (unsigned long addr);
; /* Get a byte from a location in VERA's internal address space. */
;
.export _vpeek
.import vset
.include "cx16.inc"
_vpeek: php ; (vset blocks interrupts)
jsr vset ; put VERA's address
ldx #>$0000
lda VERA::DATA0 ; read VERA port zero
plp
rts