| 75,21 → 75,17 |
|---|
| # Return 0 in EAX if CPUID is not support, 1 if supported. |
| # |
| has_cpuid: |
| pushq %rbx |
| |
| pushfq # store flags |
| popq %rax # read flags |
| movq %rax,%rbx # copy flags |
| btcl $21,%ebx # swap the ID bit |
| pushq %rbx |
| movq %rax,%rdx # copy flags |
| btcl $21,%edx # swap the ID bit |
| pushq %rdx |
| popfq # propagate the change into flags |
| pushfq |
| popq %rbx # read flags |
| popq %rdx # read flags |
| andl $(1<<21),%eax # interested only in ID bit |
| andl $(1<<21),%ebx |
| xorl %ebx,%eax # 0 if not supported, 1 if supported |
| |
| popq %rbx |
| andl $(1<<21),%edx |
| xorl %edx,%eax # 0 if not supported, 1 if supported |
| ret |
| |
| cpuid: |