msim done (ish)

1 files changed, 93 insertions, 0 deletions

diff --git a/msim/sim.c b/msim/sim.c
new file mode 100644
index 0000000..9e0d518
--- /dev/null
+++ b/msim/sim.c
@@ -0,0 +1,93 @@
+#include <merror.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "sim.h"
+#include "melf.h"
+
+void sim_dump_reg(struct simulator *sim)
+{
+	const char *names[32] = {
+		"zero", "at", "v0", "v1", "a0", "a1", "a2", "a3", "t0", "t1",
+		"t2", "t3", "t4", "t5", "t6", "t7", "s0", "s1", "s2", "s3",
+		"s4", "s5", "s6", "s7", "t8", "t9", "k0", "k1", "gp", "sp",
+		"fp", "ra"
+	};
+
+	for (uint32_t i = 0; i < 8; i++) {
+		for (uint32_t j = 0; j < 4; j++) {
+			if (j != 0)
+				fputc(' ', stderr);
+			int idx = i+j*8;
+			fprintf(stderr, "$%s:\t0x%08x", names[idx], sim->reg[idx]);
+		}
+		fputc('\n', stderr);
+	}
+}
+
+__attribute__((format(printf, 2, 3)))
+_Noreturn void sim_dump(struct simulator *sim, const char *format, ...) {
+
+	va_list list;
+	va_start(list, format);
+
+	// header
+	fprintf(stderr, "\n\t\t!!! An exception has occurred !!!\n\n");
+	fprintf(stderr, "\033[31merror: \033[0m");
+	vfprintf(stderr, format, list);
+	fputc('\n', stderr);
+
+	// pc
+	uint32_t pc = sim->current_pc;
+	fprintf(stderr, "pc: 0x%08x\n", pc);
+
+	if (pc >= sim->text_min && pc < sim->text_max)
+		fprintf(stderr, "ins: 0x%08x\n", B32(* (uint32_t *) (uintptr_t) pc));
+
+	// registers
+	fprintf(stderr, "registers:\n");
+	sim_dump_reg(sim);
+
+	exit(1);
+}
+
+void sim_step(struct simulator *sim)
+{
+	if (sim->pc < sim->text_min || sim->pc >= sim->text_max)
+		sim_dump(sim, "program counter reached non executable memory");
+
+	uint32_t ins = * (uint32_t *) (uintptr_t) sim->pc;
+	sim->pc += 4;
+	sim_ins(sim, ins);
+	sim->current_pc = sim->pc;
+}
+
+_Noreturn void sim_run(struct simulator *sim)
+{
+	sim->pc = sim->entry;
+	sim->current_pc = sim->pc;
+	while (1)
+		sim_step(sim);
+}
+
+int sim_init(struct simulator *sim, struct simulator_args *args) {
+	memset(sim->reg, 0, sizeof(uint32_t) * 32);
+	sim->data_max = MEM_DATA_ADDR;
+	sim->data_min = MEM_DATA_ADDR;
+	sim->text_max = MEM_TEXT_ADDR;
+	sim->text_min = MEM_TEXT_ADDR;
+	sim->args = args;
+
+	// load executable
+	if (sim_load_file(sim))
+		return M_ERROR;
+
+	// check entry
+	if (sim->entry < sim->text_min || sim->entry >= sim->text_max) {
+		ERROR("elf entrypoint invalid");
+		return M_ERROR;
+	}
+
+	return M_SUCCESS;
+}