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114 lines
2.0 KiB
ArmAsm
114 lines
2.0 KiB
ArmAsm
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; void* memcpy (void* dest, const void* src, size_t n);
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; void* memmove (void* dest, const void* src, size_t n);
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;
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; Ullrich von Bassewitz, 10.12.1998
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;
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.export _memcpy, _memmove
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.import popax
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.importzp ptr1, ptr2, ptr3, tmp1, tmp2
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; ----------------------------------------------------------------------
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_memcpy:
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jsr getparms ; Get the parameters from stack
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; Copy upwards
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copyup: ldy #0 ; set up to move 256
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ldx tmp2 ; hi byte of n
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beq @L2
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@L1: lda (ptr1),y ; get a byte
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sta (ptr2),y ; store it
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iny
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bne @L1
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inc ptr1+1 ; bump ptrs
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inc ptr2+1
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dex
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bne @L1 ; do another block
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@L2: ldx tmp1 ; get low byte of n
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beq done ; jump if done
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@L3: lda (ptr1),y ; get a byte
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sta (ptr2),y ; store it
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iny
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dex
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bne @L3
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done: lda ptr3
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ldx ptr3+1 ; get function result (dest)
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rts
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; ----------------------------------------------------------------------
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_memmove:
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jsr getparms ; Get the parameters from stack
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cpx ptr1+1 ; dest > src?
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bne @L1
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cmp ptr1
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@L1: beq done ; Both pointers are equal - nothing to copy
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bcc copyup ; Copy upwards
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; Copy downwards
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clc
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lda ptr1+1
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adc tmp2
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sta ptr1+1
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clc
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lda ptr2+1
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adc tmp2
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sta ptr2+1
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; Copy the incomplete page
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ldy tmp1 ; Get low byte of count
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beq @L3
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@L2: dey
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lda (ptr1),y
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sta (ptr2),y
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tya ; Test Y
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bne @L2 ; Jump if not zero
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; Copy complete pages
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@L3: ldx tmp2 ; Get hi byte of count
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beq done
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@L4: dec ptr1+1
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dec ptr2+1
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@L5: dey
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lda (ptr1),y
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sta (ptr2),y
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tya
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bne @L5
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dex
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bne @L4
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; Done
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beq done
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; ----------------------------------------------------------------------
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; Get the parameters from stack
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getparms:
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sta tmp1 ; Save n
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stx tmp2
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jsr popax ; src
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sta ptr1
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stx ptr1+1
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jsr popax ; dest
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sta ptr2
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stx ptr2+1 ; save work copy
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sta ptr3
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stx ptr3+1 ; save function result
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rts
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