Subversion Repositories planix.SVN

        TEXT    memset(SB),$12
MOVW R1, 0(FP)

/*
 * performance:
 *      about 1us/call and 28mb/sec
 */

        MOVW    n+8(FP), R3             /* R3 is count */
        MOVW    p+0(FP), R4             /* R4 is pointer */
        MOVW    c+4(FP), R5             /* R5 is char */
        ADDU    R3,R4, R6               /* R6 is end pointer */

/*
 * if not at least 4 chars,
 * dont even mess around.
 * 3 chars to guarantee any
 * rounding up to a word
 * boundary and 4 characters
 * to get at least maybe one
 * full word store.
 */
        SGT     $4,R3, R1
        BNE     R1, out

/*
 * turn R5 into a word of characters
 */
        AND     $0xff, R5
        SLL     $8,R5, R1
        OR      R1, R5
        SLL     $16,R5, R1
        OR      R1, R5

/*
 * store one byte at a time until pointer
 * is alligned on a word boundary
 */
l1:
        AND     $3,R4, R1
        BEQ     R1, l2
        MOVB    R5, 0(R4)
        ADDU    $1, R4
        JMP     l1

/*
 * turn R3 into end pointer-15
 * store 16 at a time while theres room
 */
l2:
        ADDU    $-15,R6, R3
l3:
        SGTU    R3,R4, R1
        BEQ     R1, l4
        MOVW    R5, 0(R4)
        MOVW    R5, 4(R4)
        ADDU    $16, R4
        MOVW    R5, -8(R4)
        MOVW    R5, -4(R4)
        JMP     l3

/*
 * turn R3 into end pointer-3
 * store 4 at a time while theres room
 */
l4:
        ADDU    $-3,R6, R3
l5:
        SGTU    R3,R4, R1
        BEQ     R1, out
        MOVW    R5, 0(R4)
        ADDU    $4, R4
        JMP     l5

/*
 * last loop, store byte at a time
 */
out:
        SGTU    R6,R4 ,R1
        BEQ     R1, ret
        MOVB    R5, 0(R4)
        ADDU    $1, R4
        JMP     out

ret:
        MOVW    s1+0(FP), R1
        RET
        END