Subversion Repositories or1k

!

! Fast SH memset

!

! by Toshiyasu Morita (tm@netcom.com)

!

! Entry: r4: destination pointer

!        r5: fill value

!        r6: byte count

!

! Exit:  r0-r3: trashed

!

! This assumes that the first four bytes of the address space (0..3) are

! reserved - usually by the linker script.  Otherwise, we would had to check

! for the case of objects of the size 12..15 at address 0..3 .

#include "asm.h"

ENTRY(memset)

        mov     #12,r0  ! Check for small number of bytes

        cmp/gt  r6,r0

        mov     r4,r0

        SL(bt, L_store_byte_loop_check0, add r4,r6)

        tst     #3,r0   ! Align destination

        SL(bt,  L_dup_bytes, extu.b r5,r5)

        .balignw 4,0x0009

L_align_loop:

        mov.b   r5,@r0

        add     #1,r0

        tst     #3,r0

        bf      L_align_loop

L_dup_bytes:

        swap.b  r5,r2   ! Duplicate bytes across longword

        or      r2,r5

        swap.w  r5,r2

        or      r2,r5

        add     #-16,r6

        .balignw 4,0x0009

L_store_long_loop:

        mov.l   r5,@r0  ! Store double longs to memory

        cmp/hs  r6,r0

        mov.l   r5,@(4,r0)

        SL(bf, L_store_long_loop, add #8,r0)

        add     #16,r6

L_store_byte_loop_check0:

        cmp/eq  r6,r0

        bt      L_exit

        .balignw 4,0x0009

L_store_byte_loop:

        mov.b   r5,@r0  ! Store bytes to memory

        add     #1,r0

        cmp/eq  r6,r0

        bf      L_store_byte_loop

L_exit:

        rts

        mov     r4,r0