archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-08-28 15:24:43 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

8058255: Native jbyte Atomic::cmpxchg for supported x86 platforms

Browse source 
Use the native cmpxchgb instruction on x86.

Reviewed-by: dholmes, kbarrett, phh
This commit is contained in:
Erik Osterlund 2014-10-21 15:07:25 +02:00 • committed by Jesper Wilhelmsson
parent a5d4521aa1
commit a324ff0f31
18 changed files with 165 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

11
hotspot/src/cpu/x86/vm/assembler_x86.cpp
View file

@ -1297,6 +1297,17 @@ void Assembler::cmpxchgl(Register reg, Address adr) { // cmpxchg
emit_operand(reg, adr);
}
// The 8-bit cmpxchg compares the value at adr with the contents of rax,
// and stores reg into adr if so; otherwise, the value at adr is loaded into rax,.
// The ZF is set if the compared values were equal, and cleared otherwise.
void Assembler::cmpxchgb(Register reg, Address adr) { // cmpxchg
InstructionMark im(this);
prefix(adr, reg, true);
emit_int8(0x0F);
emit_int8((unsigned char)0xB0);
emit_operand(reg, adr);
}
void Assembler::comisd(XMMRegister dst, Address src) {
// NOTE: dbx seems to decode this as comiss even though the
// 0x66 is there. Strangly ucomisd comes out correct