65 lines
1.1 KiB
ArmAsm
65 lines
1.1 KiB
ArmAsm
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!
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! Fast SH memset
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!
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! by Toshiyasu Morita (tm@netcom.com)
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!
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! Entry: r4: destination pointer
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! r5: fill value
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! r6: byte count
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!
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! Exit: r0-r3: trashed
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!
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! This assumes that the first four bytes of the address space (0..3) are
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! reserved - usually by the linker script. Otherwise, we would had to check
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! for the case of objects of the size 12..15 at address 0..3 .
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#include "asm.h"
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ENTRY(memset)
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mov #12,r0 ! Check for small number of bytes
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cmp/gt r6,r0
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mov r4,r0
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SL(bt, L_store_byte_loop_check0, add r4,r6)
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tst #3,r0 ! Align destination
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SL(bt, L_dup_bytes, extu.b r5,r5)
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.balignw 4,0x0009
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L_align_loop:
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mov.b r5,@r0
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add #1,r0
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tst #3,r0
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bf L_align_loop
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L_dup_bytes:
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swap.b r5,r2 ! Duplicate bytes across longword
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or r2,r5
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swap.w r5,r2
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or r2,r5
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add #-16,r6
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.balignw 4,0x0009
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L_store_long_loop:
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mov.l r5,@r0 ! Store double longs to memory
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cmp/hs r6,r0
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mov.l r5,@(4,r0)
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SL(bf, L_store_long_loop, add #8,r0)
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add #16,r6
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L_store_byte_loop_check0:
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cmp/eq r6,r0
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bt L_exit
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.balignw 4,0x0009
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L_store_byte_loop:
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mov.b r5,@r0 ! Store bytes to memory
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add #1,r0
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cmp/eq r6,r0
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bf L_store_byte_loop
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L_exit:
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rts
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mov r4,r0
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