mirror of
https://github.com/RevCurtisP/C02.git
synced 2024-06-26 05:29:32 +00:00
61 lines
1.5 KiB
Plaintext
61 lines
1.5 KiB
Plaintext
;c02 library stddef.h02 assembly language subroutines
|
|
;Requires External Zero Page Variables
|
|
;DSTLO, DSTHI, SRCLO, SRCHI
|
|
;External Variables
|
|
;TEMP0, TEMP1, TEMP2
|
|
|
|
;Constant Definitions
|
|
TRUE EQU $FF ;Returned for Success or Failure
|
|
FALSE EQU $00 ;by some Library Routines
|
|
|
|
;savdst() - Save Destination Pointer
|
|
SAVDST: JSR GETDST ;Load Destination Pointer
|
|
JMP SAVRXY ;Save X & Y Registers
|
|
|
|
;savdst() - Save Destination Pointer
|
|
SAVSRC: JSR GETSRC ;Load Destination Pointer
|
|
JMP SAVRXY ;Save X & Y Registers
|
|
|
|
;Save Registers
|
|
SAVREG: STA TEMP0 ;Save Accumulater
|
|
SAVRXY: STX TEMP1 ;Save X Index
|
|
STY TEMP2 ;Save Y Index
|
|
RTS
|
|
|
|
;Restore Registers
|
|
RESREG: LDA TEMP0 ;Load Accumlator
|
|
RESRXY: LDX TEMP1 ;Load X Index
|
|
LDY TEMP2 ;Load Y Index
|
|
RTS
|
|
|
|
;Restore Destination Pointer
|
|
RESDST: JSR RESRXY ;Load Address and Drop into SETDST
|
|
|
|
;Initialize Destination Pointer
|
|
SETDST: STX DSTLO ;Store Destination Pointer
|
|
STY DSTHI
|
|
RTS
|
|
|
|
;Restore Source Pointer
|
|
RESSRC: JSR RESRXY ;Load Saved Address
|
|
JMP SETSRC ;Set Source Pointer
|
|
|
|
;Set Source Pointer to Destination Pointer
|
|
SETSRD: JSR GETDST ;Get Destination Point and fall into SETSRC
|
|
|
|
;Initialize Source Pointer and Index
|
|
SETSRC: STX SRCLO ;Store Source Pointer
|
|
STY SRCHI
|
|
LDY #$00 ;Initialize Index Into String
|
|
RTS
|
|
|
|
;Retrieve Source String Pointer
|
|
GETDST: LDX DSTLO
|
|
LDY DSTHI
|
|
RTS
|
|
|
|
;Retrieve Source String Pointer
|
|
GETSRC: LDX SRCLO
|
|
LDY SRCHI
|
|
RTS
|