1 files changed, 79 insertions, 0 deletions
diff --git a/msim/debug.c b/msim/debug.c
new file mode 100644
index 0000000..1613c76
--- /dev/null
+++ b/msim/debug.c
@@ -0,0 +1,79 @@
+#include <merror.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <melf.h>
+
+#include "sim.h"
+
+static uint32_t read_num() {
+	int i = 0;
+	while (1) {
+		int c = getc(stdin);
+		if (c < '0' || c > '9') {
+			ungetc(c, stdin);
+			break;
+		}
+		i *= 10;
+		i += c - '0';
+	}
+
+	if (i)
+		return i;
+	return 1;
+}
+
+_Noreturn void sim_debug(struct simulator *sim) {
+
+	int c;
+	sim->pc = sim->entry;
+	sim->current_pc = sim->pc;
+
+prompt:
+	printf(">> ");
+	fflush(stdout);
+next:
+	switch ((c = getchar())) {
+
+	/* skip whitespace */
+	case ' ':
+	case '\t':
+		goto next;
+
+	/* ignore nl */
+	case '\n':
+		goto prompt;
+
+	/* exit on eof */
+	case EOF:
+		exit(0);
+		break;
+
+	/* dump registers */
+	case 'r':
+		sim_dump_reg(sim);
+		break;
+
+	/* step ins */
+	case 's': {
+		for (uint32_t i = read_num(); i > 0; i--)
+			sim_step(sim);
+		break;
+	}
+
+	/* print curr ins */
+	case 'i':
+		printf("0x%08x\n", B32(* (uint32_t *) (uintptr_t) sim->pc));
+		break;
+
+	case 'a':
+		printf("0x%08x\n", sim->pc);
+		break;
+
+	default:
+		ERROR("unknown command '%c'", c);
+		break;
+	}
+
+	goto next;
+}