48 lines
960 B
ArmAsm
48 lines
960 B
ArmAsm
.define Ret
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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! This subroutine stores the returnvalue in the return area.
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! This area is in zeropage.
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! The size of the object to be returned is in zeropage location
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! RETSIZE.
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! It also restores the localbases and the stackpointer of the
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! invoking procedure.
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Ret:
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sty RETSIZE ! save returnsize
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beq 1f ! the return size is zero
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lda #0 ! address of returnvalue area (highbyte)
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ldx #RETURN ! address of returnvalue area (lowbyte)
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cpy #2
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bne 2f
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jsr Sti ! store word
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jmp 1f
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2: cpy #4
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jsr Sdi ! store fourbyte word
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1: ldx LB ! get old stackpointer (lowbyte)
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stx SP+2
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lda LB+1 ! get old stackpointer (highbyte)
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sta SP+1
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inc LB
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inc LB
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bne 1f
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inc LB+1
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1: jsr Pop ! get old localbase
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stx LB ! localbase (lowbyte)
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sta LB+1 ! localbase (highbyte)
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pha
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sec
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txa
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sbc #BASE
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sta LBl ! second localbase (lowbyte)
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pla
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sbc #0
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sta LBl+1 ! second localbase (highbyte)
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rts
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