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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
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