Mercurial > hg > truffle
comparison src/cpu/x86/vm/macroAssembler_x86.cpp @ 7474:00af3a3a8df4
8005522: use fast-string instructions on x86 for zeroing
Summary: use 'rep stosb' instead of 'rep stosq' when fast-string operations are available.
Reviewed-by: twisti, roland
| author | kvn |
|---|---|
| date | Thu, 03 Jan 2013 15:09:55 -0800 |
| parents | d02120b7a34f |
| children | e2e6bf86682c |
comparison
equal
deleted
inserted
replaced
| 7473:d092d1b31229 | 7474:00af3a3a8df4 |
|---|---|
| 5222 } | 5222 } |
| 5223 #endif | 5223 #endif |
| 5224 | 5224 |
| 5225 } | 5225 } |
| 5226 | 5226 |
| 5227 void MacroAssembler::clear_mem(Register base, Register cnt, Register tmp) { | |
| 5228 // cnt - number of qwords (8-byte words). | |
| 5229 // base - start address, qword aligned. | |
| 5230 assert(base==rdi, "base register must be edi for rep stos"); | |
| 5231 assert(tmp==rax, "tmp register must be eax for rep stos"); | |
| 5232 assert(cnt==rcx, "cnt register must be ecx for rep stos"); | |
| 5233 | |
| 5234 xorptr(tmp, tmp); | |
| 5235 if (UseFastStosb) { | |
| 5236 shlptr(cnt,3); // convert to number of bytes | |
| 5237 rep_stosb(); | |
| 5238 } else { | |
| 5239 NOT_LP64(shlptr(cnt,1);) // convert to number of dwords for 32-bit VM | |
| 5240 rep_stos(); | |
| 5241 } | |
| 5242 } | |
| 5227 | 5243 |
| 5228 // IndexOf for constant substrings with size >= 8 chars | 5244 // IndexOf for constant substrings with size >= 8 chars |
| 5229 // which don't need to be loaded through stack. | 5245 // which don't need to be loaded through stack. |
| 5230 void MacroAssembler::string_indexofC8(Register str1, Register str2, | 5246 void MacroAssembler::string_indexofC8(Register str1, Register str2, |
| 5231 Register cnt1, Register cnt2, | 5247 Register cnt1, Register cnt2, |