Linus Torvalds writes: (Summary) The instruction choice is still pretty odd:
1a: f6 c3 ff test $0xff,%bl
1d: 74 02 je 21 <bar+0x21> that "test $0xff,%bl" is a rather odd way of testing the byte for zero, since that "test $0xff,%bl" is a rather odd way of testing the byte for zero, since 1a: 84 db test %bl,%bl
1c: 74 02 je 20 <bar+0x20> would have been a byte shorter and is the canonical way on x86 to test a register against zero.
a register against zero.
But that's just a "looks odd to somebody who is used to x86 asm", not a bug or anything really noticeable.
a bug or anything really noticeable.
Linus
Linus
Linus
1d: 74 02 je 21 <bar+0x21> that "test $0xff,%bl" is a rather odd way of testing the byte for zero, since that "test $0xff,%bl" is a rather odd way of testing the byte for zero, since 1a: 84 db test %bl,%bl
1c: 74 02 je 20 <bar+0x20> would have been a byte shorter and is the canonical way on x86 to test a register against zero.
a register against zero.
But that's just a "looks odd to somebody who is used to x86 asm", not a bug or anything really noticeable.
a bug or anything really noticeable.
Linus
Linus
Linus