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| author | H. Peter Anvin <hpa@zytor.com> | 2019-02-20 19:49:12 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2019-02-20 19:49:12 -0800 |
| commit | 05ac953c23f90b2328d393f7eecde96e41aed067 (patch) | |
| tree | 759fe3d75276aac5c7f9dd7dcbfb56323a85fff1 /com32 | |
| parent | 090ba3a2aa9bc3f6b5491b09f51b76836c014fee (diff) | |
| download | syslinux-master.tar.gz syslinux-master.tar.xz syslinux-master.zip | |
There is no reason to do the fairly complex flag-test sequence twice,
when we might as well check for both flags at the same time.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'com32')
| -rw-r--r-- | com32/include/x86/cpu.h | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/com32/include/x86/cpu.h b/com32/include/x86/cpu.h index 4bbcc802..f61e4389 100644 --- a/com32/include/x86/cpu.h +++ b/com32/include/x86/cpu.h @@ -6,13 +6,13 @@ #include <stdbool.h> #include <x86/regs.h> -static inline __constfunc bool cpu_has_eflag(unsigned long flag) +static inline __constfunc unsigned long cpu_has_eflags(unsigned long flags) { unsigned long f1, f2; - if (__builtin_constant_p(flag)) { - if (!(flag & ~(unsigned long)KNOWN_EFLAGS)) - return true; + if (__builtin_constant_p(flags)) { + if (!(flags & ~(unsigned long)KNOWN_EFLAGS)) + return flags; /* We know we have them all */ } asm("pushf ; " @@ -25,9 +25,14 @@ static inline __constfunc bool cpu_has_eflag(unsigned long flag) "pushf ; " "pop %1 ; " "popf" - : "=&r" (f1), "=&r" (f2) : "ri" (flag)); + : "=&r" (f1), "=&r" (f2) : "ri" (flags)); + + return (f1 ^ f2) & flags; +} - return !!((f1 ^ f2) & flag); +static inline __constfunc bool cpu_has_eflag(unsigned long flag) +{ + return cpu_has_eflags(flag) != 0; } static inline uint64_t rdtsc(void) |