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atomic: Fight with all the assemblers that don't like REP NOP. :/

This commit is contained in:
Ryan C. Gordon 2018-06-25 16:34:16 -04:00
parent 5f123e31a3
commit 58168a8c3c
1 changed files with 4 additions and 3 deletions
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7
src/atomic/SDL_spinlock.c
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@ -122,12 +122,13 @@ SDL_AtomicTryLock(SDL_SpinLock *lock)
/* "REP NOP" is PAUSE, coded for tools that don't know it by that name. */
#if (defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__))
#define PAUSE_INSTRUCTION() __asm__ __volatile__("rep nop\n")
#define PAUSE_INSTRUCTION() __asm__ __volatile__("pause\n") /* Clang lets you do REP NOP, GCC wants PAUSE. */
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
#define PAUSE_INSRUCTION() _mm_pause() /* this is actually "rep nop" and not a SIMD instruction. */
#define PAUSE_INSRUCTION() _mm_pause() /* this is actually "rep nop" and not a SIMD instruction. No inline asm in MSVC x86-64! */
#elif defined(__WATCOMC__) && defined(__386__)
/* watcom assembler won't let you do PAUSE, but refuses REP NOP as an invalid combination. Hardcode the bytes. */
extern _inline void PAUSE_INSTRUCTION(void);
#pragma aux PAUSE_INSTRUCTION = "rep nop"
#pragma aux PAUSE_INSTRUCTION = "db 0f3h,90h"
#else
#define PAUSE_INSTRUCTION()
#endif