diff options
| author | Taru Karttunen <taruti@taruti.net> | 2011-03-30 15:46:40 +0300 |
|---|---|---|
| committer | Taru Karttunen <taruti@taruti.net> | 2011-03-30 15:46:40 +0300 |
| commit | e5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch) | |
| tree | d8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/ape/lib/ap/mips/memcmp.s | |
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/ape/lib/ap/mips/memcmp.s')
| -rwxr-xr-x | sys/src/ape/lib/ap/mips/memcmp.s | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/sys/src/ape/lib/ap/mips/memcmp.s b/sys/src/ape/lib/ap/mips/memcmp.s new file mode 100755 index 000000000..c9142f85e --- /dev/null +++ b/sys/src/ape/lib/ap/mips/memcmp.s @@ -0,0 +1,114 @@ + TEXT memcmp(SB), $0 +MOVW R1, 0(FP) + +/* + * performance: + * alligned about 1.0us/call and 17.4mb/sec + * unalligned is about 3.1mb/sec + */ + + MOVW n+8(FP), R3 /* R3 is count */ + MOVW s1+0(FP), R4 /* R4 is pointer1 */ + MOVW s2+4(FP), R5 /* R5 is pointer2 */ + ADDU R3,R4, R6 /* R6 is end pointer1 */ + +/* + * 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 cmp. + */ + SGT $4,R3, R1 + BNE R1, out + +/* + * test if both pointers + * are similarly word alligned + */ + XOR R4,R5, R1 + AND $3, R1 + BNE R1, out + +/* + * byte at a time to word allign + */ +l1: + AND $3,R4, R1 + BEQ R1, l2 + MOVB 0(R4), R8 + MOVB 0(R5), R9 + ADDU $1, R4 + BNE R8,R9, ne + ADDU $1, R5 + JMP l1 + +/* + * turn R3 into end pointer1-15 + * cmp 16 at a time while theres room + */ +l2: + ADDU $-15,R6, R3 +l3: + SGTU R3,R4, R1 + BEQ R1, l4 + MOVW 0(R4), R8 + MOVW 0(R5), R9 + MOVW 4(R4), R10 + BNE R8,R9, ne + MOVW 4(R5), R11 + MOVW 8(R4), R8 + BNE R10,R11, ne1 + MOVW 8(R5), R9 + MOVW 12(R4), R10 + BNE R8,R9, ne + MOVW 12(R5), R11 + ADDU $16, R4 + BNE R10,R11, ne1 + BNE R8,R9, ne + ADDU $16, R5 + JMP l3 + +/* + * turn R3 into end pointer1-3 + * cmp 4 at a time while theres room + */ +l4: + ADDU $-3,R6, R3 +l5: + SGTU R3,R4, R1 + BEQ R1, out + MOVW 0(R4), R8 + MOVW 0(R5), R9 + ADDU $4, R4 + BNE R8,R9, ne /* only works because big endian */ + ADDU $4, R5 + JMP l5 + +/* + * last loop, cmp byte at a time + */ +out: + SGTU R6,R4, R1 + BEQ R1, ret + MOVB 0(R4), R8 + MOVB 0(R5), R9 + ADDU $1, R4 + BNE R8,R9, ne + ADDU $1, R5 + JMP out + +ne1: + SGTU R10,R11, R1 + BNE R1, ret + MOVW $-1,R1 + RET +ne: + SGTU R8,R9, R1 + BNE R1, ret + MOVW $-1,R1 +ret: + RET + END |