| 44,6 → 44,39 |
|---|
| movq $halt, (%rsp) |
| jmp printf |
| |
| .global has_cpuid |
| .global rdtsc |
| |
| |
| ## Determine CPUID support |
| # |
| # 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 |
| popfq # propagate the change into flags |
| pushfq |
| popq %rbx # 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 |
| ret |
| |
| |
| rdtsc: |
| xorq %rax,%rax |
| rdtsc |
| ret |
| |
| |
| # Push all general purpose registers on stack except %rbp, %rsp |
| .macro push_all_gpr |
| pushq %rax |