From e281c39d24793ea5793b0eabdd684c5e12ea77fe Mon Sep 17 00:00:00 2001 From: Michael Smith Date: Wed, 11 Nov 2026 22:24:54 +0000 Subject: Add a mem_copy_fixed and mem_set_fixed to mem.h Probably self-explanatory. I was finding more use cases for the __builtin_memcpy_inline thing but boy is that ugly. --- src/mem.h | 22 ++++++++++++++++++++++ src/speedrun.c | 3 +-- src/sst.c | 6 ++---- 3 files changed, 25 insertions(+), 6 deletions(-) (limited to 'src') diff --git a/src/mem.h b/src/mem.h index ae33092..553d390 100644 --- a/src/mem.h +++ b/src/mem.h @@ -223,6 +223,28 @@ static forceinline int mem_cmp(const void *restrict x, const void *restrict y, #endif } +/* + * Copies a small fixed-size chunk of memory using some appropriate + * compiler-chosen arrangement of move instructions, without calling any + * functions. Length must be a compile-time constant. + */ +#ifdef __clang__ +#define mem_copy_fixed __builtin_memcpy_inline +#else +#define mem_copy_fixed mem_copy // meh +#endif + +/* + * Sets a small fixed-size chunk of memory using some appropriate + * compiler-chosen arrangement of instructions, without calling any + * functions. Length and value must be compile-time constants. + */ +#ifdef __clang__ +#define mem_set_fixed __builtin_memcpy_inline +#else +#define mem_set_fixed mem_set // meh +#endif + #endif // vi: sw=4 ts=4 noet tw=80 cc=80 diff --git a/src/speedrun.c b/src/speedrun.c index a0849dd..87942e2 100644 --- a/src/speedrun.c +++ b/src/speedrun.c @@ -186,8 +186,7 @@ DEF_CCMD_HERE(sst_speedrun_start, "Start recording demos for a speedrun", 0) { else { nameend = pathsz + namelen; } - __builtin_memcpy_inline(path + nameend, OS_LIT(".dem"), - sizeof(OS_LIT(".dem"))); + mem_copy_fixed(path + nameend, OS_LIT(".dem"), sizeof(OS_LIT(".dem"))); // check for an existing demo file with this name: if we started // recording, then stopped, then started again in quick succession, we // could have one. in this scenario, append a 2-digit counter to the end diff --git a/src/sst.c b/src/sst.c index ab78b9c..4cdad5d 100644 --- a/src/sst.c +++ b/src/sst.c @@ -197,11 +197,9 @@ c: mem_copy(r, p + slash + 1, rellen); if_cold (f == -1) { errmsg_errorsys("couldn't open %" fS, path); return; } #ifdef _WIN32 char buf[19 + PATH_MAX]; - // XXX: with actual calls to memcpy gone, we need this builtin to produce 4 - // 4-byte movs from this string; can we expose this in a less hideous way? - __builtin_memcpy_inline(buf, "Plugin { file \"", 15); + mem_copy_fixed(buf, "Plugin { file \"", 15); for (int i = 0; i < rellen; ++i) buf[i + 15] = relpath[i]; - __builtin_memcpy_inline(buf + 15 + rellen, "\" }\n", 4); + mem_copy_fixed(buf + 15 + rellen, "\" }\n", 4); if_cold (os_write(f, buf, rellen + 19) == -1) { // blegh #else struct iovec iov[3] = { -- cgit v1.2.3-54-g00ecf