msim done (ish)

1 files changed, 87 insertions, 0 deletions

diff --git a/msim/sim.h b/msim/sim.h
new file mode 100644
index 0000000..517babd
--- /dev/null
+++ b/msim/sim.h
@@ -0,0 +1,87 @@
+/* Copyright (c) 2024 Freya Murphy */
+
+#ifndef __SIM_H__
+#define __SIM_H__
+
+#include <elf.h>
+#include <stdint.h>
+
+/// arguments
+struct simulator_args {
+	char *executable;
+	bool memchk;
+	bool debug;
+};
+
+
+// when loading the executable, we need to bounds check to
+// make sure its within the file size
+//
+// this checks that
+// 1. the end is in the file
+// 2. the off and len doesnt integer overflow
+#define BOUND_CHK(size, len, off) \
+	((off) > UINT32_MAX - (len) || (off) + (len) > (size))
+
+///
+/// data must start at these
+/// addresses or the executable is
+/// invalid
+///
+#define MEM_TEXT_ADDR 0x00400000
+#define MEM_DATA_ADDR 0x10000000
+
+struct simulator {
+	struct simulator_args *args;
+
+
+	/// the registers
+	uint32_t reg[32];
+
+	/// the program counter
+	uint32_t pc;
+
+	/// the current executing pc
+	uint32_t current_pc;
+
+	/// low and hi
+	uint32_t low;
+	uint32_t hi;
+
+	/// memory address bounds
+	uint32_t data_min;
+	uint32_t data_max;
+	uint32_t text_min;
+	uint32_t text_max;
+
+	// entrypoint
+	uint32_t entry;
+};
+
+/* initalize a simulator */
+int sim_init(struct simulator *sim, struct simulator_args *args);
+
+/* load a file into a simulator */
+int sim_load_file(struct simulator *sim);
+
+/* execute and instruction */
+void sim_ins(struct simulator *sim, uint32_t ins);
+
+/* execute the next instruction in the simulator */
+void sim_step(struct simulator *sim);
+
+/* run the simulator with the loaded state */
+_Noreturn void sim_run(struct simulator *sim);
+
+/* run the debugger for a simulator */
+_Noreturn void sim_debug(struct simulator *sim);
+
+/* panics the simulator */
+__attribute__((format(printf, 2, 3)))
+_Noreturn void sim_dump(struct simulator *sim, const char *format, ...);
+
+/* dumps registers */
+void sim_dump_reg(struct simulator *sim);
+
+#endif /* __SIM_H__ */
+