Mercurial > hg > truffle
diff src/cpu/x86/vm/x86_64.ad @ 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 | f6badecb7ea7 |
| children | b30b3c2a0cf2 |
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--- a/src/cpu/x86/vm/x86_64.ad Sun Dec 23 17:08:22 2012 +0100 +++ b/src/cpu/x86/vm/x86_64.ad Thu Jan 03 15:09:55 2013 -0800 @@ -10374,16 +10374,33 @@ instruct rep_stos(rcx_RegL cnt, rdi_RegP base, rax_RegI zero, Universe dummy, rFlagsReg cr) %{ + predicate(!UseFastStosb); match(Set dummy (ClearArray cnt base)); effect(USE_KILL cnt, USE_KILL base, KILL zero, KILL cr); - format %{ "xorl rax, rax\t# ClearArray:\n\t" - "rep stosq\t# Store rax to *rdi++ while rcx--" %} - ins_encode(opc_reg_reg(0x33, RAX, RAX), // xorl %eax, %eax - Opcode(0xF3), Opcode(0x48), Opcode(0xAB)); // rep REX_W stos + format %{ "xorq rax, rax\t# ClearArray:\n\t" + "rep stosq\t# Store rax to *rdi++ while rcx--" %} + ins_encode %{ + __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register); + %} ins_pipe(pipe_slow); %} +instruct rep_fast_stosb(rcx_RegL cnt, rdi_RegP base, rax_RegI zero, Universe dummy, + rFlagsReg cr) +%{ + predicate(UseFastStosb); + match(Set dummy (ClearArray cnt base)); + effect(USE_KILL cnt, USE_KILL base, KILL zero, KILL cr); + format %{ "xorq rax, rax\t# ClearArray:\n\t" + "shlq rcx,3\t# Convert doublewords to bytes\n\t" + "rep stosb\t# Store rax to *rdi++ while rcx--" %} + ins_encode %{ + __ clear_mem($base$$Register, $cnt$$Register, $zero$$Register); + %} + ins_pipe( pipe_slow ); +%} + instruct string_compare(rdi_RegP str1, rcx_RegI cnt1, rsi_RegP str2, rdx_RegI cnt2, rax_RegI result, regD tmp1, rFlagsReg cr) %{