diff options
Diffstat (limited to 'libkern/memmove-power.s')
| -rw-r--r-- | libkern/memmove-power.s | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/libkern/memmove-power.s b/libkern/memmove-power.s new file mode 100644 index 00000000..1b27e5d6 --- /dev/null +++ b/libkern/memmove-power.s @@ -0,0 +1,170 @@ +#define BDNZ BC 16,0, + TEXT memcpy(SB), $0 + BR move + + TEXT memmove(SB), $0 +move: + +/* + * performance: + * (tba) + */ + + MOVW R3, s1+0(FP) + MOVW n+8(FP), R9 /* R9 is count */ + MOVW R3, R10 /* R10 is to-pointer */ + CMP R9, $0 + BEQ ret + BLT trap + MOVW s2+4(FP), R11 /* R11 is from-pointer */ + +/* + * if no more than 16 bytes, just use one lsw/stsw + */ + CMP R9, $16 + BLE fout + + ADD R9,R11, R13 /* R13 is end from-pointer */ + ADD R9,R10, R12 /* R12 is end to-pointer */ + +/* + * easiest test is copy backwards if + * destination string has higher mem address + */ + CMPU R10, R11 + BGT back + +/* + * test if both pointers + * are similarly word aligned + */ + XOR R10,R11, R7 + ANDCC $3,R7 + BNE fbad + +/* + * move a few bytes to align pointers + */ + ANDCC $3,R10,R7 + BEQ f2 + SUBC R7, $4, R7 + SUB R7, R9 + MOVW R7, XER + LSW (R11), R16 + ADD R7, R11 + STSW R16, (R10) + ADD R7, R10 + +/* + * turn R14 into doubleword count + * copy 16 bytes at a time while there's room. + */ +f2: + SRAWCC $4, R9, R14 + BLE fout + MOVW R14, CTR + SUB $4, R11 + SUB $4, R10 +f3: + MOVWU 4(R11), R16 + MOVWU R16, 4(R10) + MOVWU 4(R11), R17 + MOVWU R17, 4(R10) + MOVWU 4(R11), R16 + MOVWU R16, 4(R10) + MOVWU 4(R11), R17 + MOVWU R17, 4(R10) + BDNZ f3 + RLWNMCC $0, R9, $15, R9 /* residue */ + BEQ ret + ADD $4, R11 + ADD $4, R10 + +/* + * move up to 16 bytes through R16 .. R19; aligned and unaligned + */ +fout: + MOVW R9, XER + LSW (R11), R16 + STSW R16, (R10) + BR ret + +/* + * loop for unaligned copy, then copy up to 15 remaining bytes + */ +fbad: + SRAWCC $4, R9, R14 + BLE f6 + MOVW R14, CTR +f5: + LSW (R11), $16, R16 + ADD $16, R11 + STSW R16, $16, (R10) + ADD $16, R10 + BDNZ f5 + RLWNMCC $0, R9, $15, R9 /* residue */ + BEQ ret +f6: + MOVW R9, XER + LSW (R11), R16 + STSW R16, (R10) + BR ret + +/* + * whole thing repeated for backwards + */ +back: + CMP R9, $4 + BLT bout + + XOR R12,R13, R7 + ANDCC $3,R7 + BNE bout +b1: + ANDCC $3,R13, R7 + BEQ b2 + MOVBZU -1(R13), R16 + MOVBZU R16, -1(R12) + SUB $1, R9 + BR b1 +b2: + SRAWCC $4, R9, R14 + BLE b4 + MOVW R14, CTR +b3: + MOVWU -4(R13), R16 + MOVWU R16, -4(R12) + MOVWU -4(R13), R17 + MOVWU R17, -4(R12) + MOVWU -4(R13), R16 + MOVWU R16, -4(R12) + MOVWU -4(R13), R17 + MOVWU R17, -4(R12) + BDNZ b3 + RLWNMCC $0, R9, $15, R9 /* residue */ + BEQ ret +b4: + SRAWCC $2, R9, R14 + BLE bout + MOVW R14, CTR +b5: + MOVWU -4(R13), R16 + MOVWU R16, -4(R12) + BDNZ b5 + RLWNMCC $0, R9, $3, R9 /* residue */ + BEQ ret + +bout: + CMPU R13, R11 + BLE ret + MOVBZU -1(R13), R16 + MOVBZU R16, -1(R12) + BR bout + +trap: +/* MOVW $0, R0 */ + MOVW R0, 0(R0) + +ret: + MOVW s1+0(FP), R3 + RETURN |