From 8d4b47298b6c9eeb9a3f79a5b80d894f80ed4a45 Mon Sep 17 00:00:00 2001 From: Michael Smith Date: Sat, 27 Dec 2025 03:05:05 +0000 Subject: Do away with memcpy/memset/memcmp Now everything is either explicitly a rep thing, or explicitly some other small run of reasonably efficient instructions. No library calls or function call overhead of any kind. Code size remains nice and small. Ban a few other bad libc functions while we're at it. More can be added later if we decide that's a useful idea. This will require some discipline and workarounds to cope with Clang's tendency to shove mem* calls in places you don't want them even when you tell it not to. Well, c'est la vie. I'm a little nervous that the __builtin_memmove() usage in shuntvars() could still one day emit actual library calls. It appears we're not importing memmove() from anywhere at the moment, though. So I guess it's good enough for now. Also I had to get rid of alloca() in con_.c but that was kind of bad anyway, so that's fine. --- src/l4d1democompat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'src/l4d1democompat.c') diff --git a/src/l4d1democompat.c b/src/l4d1democompat.c index a6d418f..735215c 100644 --- a/src/l4d1democompat.c +++ b/src/l4d1democompat.c @@ -127,8 +127,9 @@ static inline ReadDemoHeader_func find_ReadDemoHeader(const uchar *insns) { static inline void *find_midpoint(ReadDemoHeader_func ReadDemoHeader) { uchar *insns = (uchar *)ReadDemoHeader; for (uchar *p = insns; p - insns < 128;) { + const u64 HL2DEMO = 0x4F4D4544324C48; // "HL2DEMO\0" ascii, little-endian if (p[0] == X86_PUSHIW && p[5] == X86_PUSHEBX && p[6] == X86_CALL && - !memcmp(mem_loadptr(p + 1), "HL2DEMO", 7)) { + !mem_loadu64(mem_loadptr(p + 1)) == HL2DEMO) { return p + 11; } NEXT_INSN(p, "ReadDemoHeader hook midpoint"); -- cgit v1.2.3-54-g00ecf