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!
! Fast SH memset
!
! by Toshiyasu Morita (tm@netcom.com)
!
! SH5 code by J"orn Rennecke (joern.rennecke@superh.com)
! Copyright 2002 SuperH Ltd.
!

#include "asm.h"

ENTRY(memset)
#if __SHMEDIA__
        pta/l multiquad, tr0
        ptabs r18, tr2

        andi r2, -8, r25
        add r2, r4, r5
        addi r5, -1, r20    // calculate end address.
        andi r20, -8, r20
        cmveq r4, r25, r20
        bne/u r25, r20, tr0 // multiquad

!       This sequence could clobber volatile objects that are in the same
!       quadword as a very short char array.
!       ldlo.q r2, 0, r7
!       shlli r4, 2, r4
!       movi -1, r8
!       SHHI r8, r4, r8
!       SHHI r8, r4, r8
!       mcmv r7, r8, r3
!       stlo.q r2, 0, r3

        pta/l setlongs, tr0
        movi 4, r8
        bgeu/u r4, r8, tr0
        pta/l endset, tr0
        beqi/u r4, 0, tr0
        st.b r2, 0, r3
        beqi/u r4, 1, tr0
        nop
        st.b r2, 1, r3
        beqi/l r4, 2, tr0
        st.b r2,2,r3
endset: blink tr2, r63
setlongs:
        mshflo.b r3, r3, r3
        mperm.w r3, r63, r3     // Fill pattern now in every byte of r3
        stlo.l r2, 0, r3
        nop
        nop
        sthi.l r5, -1, r3
        blink tr2, r63

multiquad:
        mshflo.b r3, r3, r3
        mperm.w r3, r63, r3     // Fill pattern now in every byte of r3
        pta/l lastquad, tr0
        stlo.q r2, 0, r3
        sub r20, r25, r24
        movi 64, r9
        beqi/u r24, 8, tr0 // lastquad
        pta/l loop, tr1
        addi r20, -7*8, r8 // loop end address; This might overflow, so we need
                           // to use a different test before we start the loop
        bgeu/u r24, r9, tr1// loop
        st.q r25, 8, r3
        shlri r24, 4, r24
        st.q r20, -8, r3
        beqi/u r24, 1, tr0 // lastquad
        st.q r25, 16, r3
        st.q r20, -16, r3
        beqi/u r24, 2, tr0 // lastquad
        st.q r25, 24, r3
        st.q r20, -24, r3
lastquad:
        sthi.q r5, -1, r3
        blink tr2,r63

loop:
        alloco r25, 32
        st.q r25, 8, r3
        st.q r25, 16, r3
        st.q r25, 24, r3
        st.q r25, 32, r3
        addi r25, 32, r25
        bgeu/l r8, r25, tr1 // loop

        st.q r20, -40, r3
        st.q r20, -32, r3
        st.q r20, -24, r3
        st.q r20, -16, r3
        st.q r20, -8, r3
        sthi.q r5, -1, r3
        blink tr2,r63
#else /* ! SHMEDIA, i.e. SH1 .. SH4 / SHcompact */
! 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 .

#ifdef __SH5__
#define DST r2
#define VAL r3
#define CNT r4
#define TMP r5
#else
#define DST r4
#define VAL r5
#define CNT r6
#define TMP r2
#endif

        mov     #12,r0  ! Check for small number of bytes
        cmp/gt  CNT,r0
        mov     DST,r0
        SL(bt, L_store_byte_loop_check0, add DST,CNT)

        tst     #3,r0   ! Align destination
        SL(bt,  L_dup_bytes, extu.b r5,r5)
        .balignw 4,0x0009
L_align_loop:
        mov.b   VAL,@r0
        add     #1,r0
        tst     #3,r0
        bf      L_align_loop

L_dup_bytes:    
        swap.b  VAL,TMP ! Duplicate bytes across longword
        or      TMP,VAL
        swap.w  VAL,TMP
        or      TMP,VAL

        add     #-16,CNT

        .balignw 4,0x0009
L_store_long_loop:
        mov.l   VAL,@r0 ! Store double longs to memory
        cmp/hs  CNT,r0
        mov.l   VAL,@(4,r0)
        SL(bf, L_store_long_loop, add #8,r0)

        add     #16,CNT

L_store_byte_loop_check0:
        cmp/eq  CNT,r0
        bt      L_exit
        .balignw 4,0x0009
L_store_byte_loop:
        mov.b   VAL,@r0 ! Store bytes to memory
        add     #1,r0
        cmp/eq  CNT,r0
        bf      L_store_byte_loop

L_exit:
        rts
        mov     r4,r0
#endif /* ! SHMEDIA */