Status: New
Owner: ----
New issue 1495 by [email protected]: Smaller instruction for write barrier
(ia32)
http://code.google.com/p/v8/issues/detail?id=1495
0xf53e9d45 69 f6c101 test_b cl,1
0xf53e9d48 72 7429 jz 115 (0xf53e9d73)
0xf53e9d4a 74 8d8a0000000a lea ecx,[edx+0xa000000]
0xf53e9d50 80 81e1000000ff and ecx,0xff000000
0xf53e9d56 86 741b jz 115 (0xf53e9d73)
0xf53e9d58 88 8d5a1b lea ebx,[edx+27]
0xf53e9d5b 91 81e200e0ffff and edx,0xffffe000
0xf53e9d61 97 81e3ff1f0000 and ebx,0x1fff ***
0xf53e9d67 103 c1eb08 shr ebx,8 ***
0xf53e9d6a 106 8b4a08 mov ecx,[edx+8]
0xf53e9d6d 109 0fabd9 bts ecx,ebx
0xf53e9d70 112 894a08 mov [edx+8],ecx
*** Save 3 bytes:
shr ebx,8
and ebx,0x1f // short form
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