Hello, MSVC and ICC (currently Windows version, Linux version soon) have dedicated intrinsics to read/set EFLAGS register ([1], [2]).
Patch introduces these intrinsics and tests for them. Bootstrapped. New tests pass. Although gate is closed patch is obvious. So, is it ok for trunk? ChangeLog/ * config/i386/ia32intrin.h (__readeflags): New. (__writeeflags): Ditto. testsuite/ChangeLog/ * gcc.target/i386/readeflags-1.c: New. * gcc.target/i386/writeeflags-1.c: Ditto. [1] - http://msdn.microsoft.com/en-us/library/aa983406(v=vs.90).aspx [2] - http://msdn.microsoft.com/en-us/library/aa983392(v=vs.90).aspx -- Thanks, K diff --git a/gcc/config/i386/ia32intrin.h b/gcc/config/i386/ia32intrin.h index b26dc46..c9e68c5 100644 --- a/gcc/config/i386/ia32intrin.h +++ b/gcc/config/i386/ia32intrin.h @@ -238,6 +238,34 @@ __rorq (unsigned long long __X, int __C) return (__X >> __C) | (__X << (64 - __C)); } +/* Read flags register */ +extern __inline unsigned long long +__attribute__((__gnu_inline__, __always_inline__, __artificial__)) +__readeflags (void) +{ + unsigned long long result = 0; + __asm__ __volatile__ ("pushf\n\t" + "popq %0\n" + :"=r"(result) + : + : + ); + return result; +} + +/* Write flags register */ +extern __inline void +__attribute__((__gnu_inline__, __always_inline__, __artificial__)) +__writeeflags (unsigned long long X) +{ + __asm__ __volatile__ ("pushq %0\n\t" + "popf\n" + : + :"r"(X) + :"flags" + ); +} + #define _bswap64(a) __bswapq(a) #define _popcnt64(a) __popcntq(a) #define _lrotl(a,b) __rolq((a), (b)) @@ -245,6 +273,35 @@ __rorq (unsigned long long __X, int __C) #else #define _lrotl(a,b) __rold((a), (b)) #define _lrotr(a,b) __rord((a), (b)) + +/* Read flags register */ +extern __inline unsigned int +__attribute__((__gnu_inline__, __always_inline__, __artificial__)) +__readeflags (void) +{ + unsigned int result = 0; + __asm__ __volatile__ ("pushf\n\t" + "popl %0\n" + :"=r"(result) + : + : + ); + return result; +} + +/* Write flags register */ +extern __inline void +__attribute__((__gnu_inline__, __always_inline__, __artificial__)) +__writeeflags (unsigned int X) +{ + __asm__ __volatile__ ("pushl %0\n\t" + "popf\n" + : + :"r"(X) + :"flags" + ); +} + #endif #define _bit_scan_forward(a) __bsfd(a) diff --git a/gcc/testsuite/gcc.target/i386/readeflags-1.c b/gcc/testsuite/gcc.target/i386/readeflags-1.c new file mode 100644 index 0000000..6b2fa7e --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/readeflags-1.c @@ -0,0 +1,40 @@ +/* { dg-do run } */ +/* { dg-options "-O0" } */ + +#include <x86intrin.h> + +#ifdef __x86_64__ +#define EFLAGS_TYPE unsigned long long int +#else +#define EFLAGS_TYPE unsigned int +#endif + +static EFLAGS_TYPE +readeflags_test (unsigned int a, unsigned int b) +{ + unsigned x = (a == b); + return __readeflags (); +} + +int +main () +{ + EFLAGS_TYPE flags; + + flags = readeflags_test (100, 100); + + if ((flags & 1) != 0) /* Read CF */ + abort (); + + flags = readeflags_test (100, 101); + + if ((flags & 1) == 0) /* Read CF */ + abort (); + +#ifdef DEBUG + printf ("PASSED\n"); +#endif + + return 0; +} + diff --git a/gcc/testsuite/gcc.target/i386/writeeflags-1.c b/gcc/testsuite/gcc.target/i386/writeeflags-1.c new file mode 100644 index 0000000..446840c --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/writeeflags-1.c @@ -0,0 +1,30 @@ +/* { dg-do run } */ +/* { dg-options "-O0" } */ + +#include <x86intrin.h> + +#ifdef __x86_64__ +#define EFLAGS_TYPE unsigned long long int +#else +#define EFLAGS_TYPE unsigned int +#endif + +int +main () +{ + EFLAGS_TYPE flags = 0xD7; /* 111010111b */ + + __writeeflags (flags); + + flags = __readeflags (); + + if ((flags & 0xFF) != 0xD7) + abort (); + +#ifdef DEBUG + printf ("PASSED\n"); +#endif + + return 0; +} +