mirrors/SDL
1
0
Fork 0
mirror of https://github.com/libsdl-org/SDL.git synced 2025-10-26 12:27:44 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fix memory barriers on ARMv5

Browse Source 
The ARM926EJ-S Technical Reference Manual states:

> You can only access CP15 registers with MRC and MCR instructions in a
> privileged mode. CDP, LDC, STC, MCRR, and MRRC instructions, and unprivileged
> MRC or MCR instructions to CP15 cause the Undefined instruction exception to
> be taken.

Furthermore, `MCR p15, 0, <Rd>, c7, c10, 5` (later called Data Memory Barrier)
is not specified for the ARM926. Thus, SDL should not use these cache
instructions on ARMv5.
This commit is contained in:
J. Neuschäfer
2024-01-05 06:30:54 +01:00
committed by Sam Lantinga
parent 21c80ac843
commit 139a0931a3
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/SDL3/SDL_atomic.h
View File

@@ -213,7 +213,7 @@ typedef void (*SDL_KernelMemoryBarrierFunc)();
#if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7EM__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) || defined(__ARM_ARCH_8A__) #if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7EM__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) || defined(__ARM_ARCH_8A__)
#define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("dmb ish" : : : "memory") #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("dmb ish" : : : "memory")
#define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("dmb ish" : : : "memory") #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("dmb ish" : : : "memory")
#elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_5TE__) #elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__)
#ifdef __thumb__ #ifdef __thumb__
/* The mcr instruction isn't available in thumb mode, use real functions */ /* The mcr instruction isn't available in thumb mode, use real functions */
#define SDL_MEMORY_BARRIER_USES_FUNCTION #define SDL_MEMORY_BARRIER_USES_FUNCTION