X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=ROM2%2Fhelpers.c;h=ad52123b97a39a1eed528036a861948c5344c75a;hb=f5bc521c83d95d35e852747402a44d1411252c2b;hp=07ab7f4da859c3a5803b36b9ad853f2b07017a42;hpb=cef1445c4f1ebaa38f9e6561b4fd15f164a27dcd;p=uccvend-snackrom.git

diff --git a/ROM2/helpers.c b/ROM2/helpers.c
index 07ab7f4..ad52123 100644
--- a/ROM2/helpers.c
+++ b/ROM2/helpers.c
@@ -1,11 +1,52 @@
+#include "display_basic.h"
 #include "vend.h"
 
-#define DELAY_MAGIC 20 /* FIXME: number of loops required for ~ 1 millisecond */
 void delay(u16 ms) {
-	int i;
-	for (;ms;ms--) {
-		for (i=0;i<DELAY_MAGIC; i++)
-			asm("nop\nnop\nnop\nnop\nnop\n");
+	/* delay routine written in assembly so we know what we're really getting.
+	 * each inner loop should take ~1 ms to execute.
+	 * 15 cycles * (1/4.9152Mhz) * 327 = 0.997 ms + a little bit on the fringes.
+	 *
+	 * XXX - how do we know gcc isn't optimising this? it seems to optimise after
+	 * parsing C -> asm, but before asm -> machine code.
+	 */
+	//asm volatile ("pshx\npsha\npshb\n"); /* save registers */
+	asm volatile ("ldx %0\n" :: "m" (ms) : "x");
+	asm volatile (
+		"delay_loop:\n"
+		"	dex\n"                        /* 3 */
+		"	beq delay_out\n"              /* 3 */
+		//"	ldd #327\n"                   /* 3 */
+		"	ldd #150\n"                   /* 3 */
+		"delay_inner_loop:\n" /* 15 cycles each */
+		"	cpd #0x0000\n"                /* 5 */
+		"	beq delay_inner_loop_end\n"   /* 3 */
+		"	subd #0x0001\n"               /* 4 */
+		"	bra delay_inner_loop\n"       /* 3 */
+		"delay_inner_loop_end:\n"
+		"	bra delay_loop\n"             /* 3 */
+		"delay_out:\n" ::: "x", "d");
+		/*"	pulb\n"
+		"	pula\n"
+		"	pulx\n");*/
+}
+
+void my_strncpy(char* dst, char* src, u8 max_size) {
+	u8 i;
+	for (i = 0; src[i] && i < max_size; i++) dst[i] = src[i];
+	if (src[i] == 0 && i < max_size) dst[i] = 0; /* null terminator */
+}
+
+bool my_strncmp(char* a, char* b, u8 len) {
+	u8 i;
+	for (i = 0; i < len; i++) {
+		if (*a != *b) return 0;
+		a++;
+		b++;
 	}
+	return 1;
 }
 
+void my_memcpy(char* dst, char* src, u8 size) {
+	u8 i = 0;
+	for (i = 0; i < size; i++) dst[i] = src[i];
+}