Implement initial versionv1.0

1 files changed, 37 insertions, 0 deletions

diff --git a/src/wincrt.c b/src/wincrt.c
new file mode 100644
index 0000000..ae24045
--- /dev/null
+++ b/src/wincrt.c
@@ -0,0 +1,37 @@
+/* This file is dedicated to the public domain. */
+
+// TODO(opt): this feels like a sad implementation, can we do marginally better?
+int memcmp(const void *x_, const void *y_, unsigned int sz) {
+	const char *x = x_, *y = y_;
+	for (unsigned int i = 0; i < sz; ++i) {
+		if (x[i] > y[i]) return 1;
+		if (x[i] < y[i]) return -1;
+	}
+	return 0;
+}
+
+void *memcpy(void *restrict x, const void *restrict y, unsigned int sz) {
+#ifdef __clang__
+	__asm__ volatile (
+		"rep movsb\n" :
+		"=D" (x), "=S" (y), "=c" (sz) :
+		"0" (x), "1" (y), "2" (sz) :
+		"memory"
+	);
+#else // terrible fallback just in case someone wants to use this with MSVC
+	char *restrict xb = x; const char *restrict yb = y;
+	for (unsigned int i = 0; i < sz; ++i) xb[i] = yb[i];
+#endif
+	return x;
+}
+
+// this was briefly needed at some point in debugging but seems to be gone again
+// (hence crappy impl). if compiler starts calling memset with opts on, we
+// should use a proper rep stosb impl as well
+//void *memset(void *x, int c, unsigned int n) {
+//	char *xb = x;
+//	for (; n; ++xb, --n) *xb = c;
+//	return x;
+//}
+
+// vi: sw=4 ts=4 noet tw=80 cc=80