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47 lines
488 B
ArmAsm
47 lines
488 B
ArmAsm
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; Ullrich von Bassewitz, 1998-09-17, 2005-02-26.
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;
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; Zero the bss segment.
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;
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.export zerobss
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.import __BSS_RUN__, __BSS_SIZE__
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.importzp ptr1
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.segment "INIT"
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zerobss:
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lda #<__BSS_RUN__
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sta ptr1
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lda #>__BSS_RUN__
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sta ptr1+1
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lda #0
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tay
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; Clear full pages
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L1: ldx #>__BSS_SIZE__
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beq L3
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L2: sta (ptr1),y
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iny
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bne L2
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inc ptr1+1
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dex
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bne L2
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; Clear remaining page (y is zero on entry)
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L3: cpy #<__BSS_SIZE__
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beq L4
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sta (ptr1),y
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iny
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bne L3
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; Done
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L4: rts
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