26 Jul
2019
26 Jul
'19
2:07 p.m.
On 7/26/19, Peter Zijlstra peterz@infradead.org wrote:
On Fri, Jul 26, 2019 at 01:18:06PM +0300, Jari Ruusu wrote:
Shouldn't those clobber contraints actually be: "memory","cc" That is because addl subl (and other) machine instructions actually modify the flags register too.
gcc docs say: The "cc" clobber indicates that the assembler code modifies the flags register.
GCC x86 assumes any asm() will clobber "cc".
No worries then. Thanks for your clarification.
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Jari Ruusu 4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD ACDF F073 3C80 8132 F189