#include <stdio.h>
#include <inttypes.h>

#include "../deps/ejit/include/ejit/ejit.h"

static struct ejit_func *compile(const char *program)
{
	struct ejit_func *func = ejit_create_func(EJIT_INT32, 0, NULL);
	if (!func) {
		fprintf(stderr, "failed allocating func\n");
		return NULL;
	}

	/* initialize accumulator */
	ejit_movi(func, EJIT_GPR(0), 0);

	/* load constant 2 into register for multiplication/division since ejit
	 * doesn't have muli/divi instructions */
	ejit_movi(func, EJIT_GPR(1), 2);

	char c = 0;
	while ((c = *program++))
	switch (c) {
	case '+': ejit_addi(func, EJIT_GPR(0), EJIT_GPR(0), 1); break;
	case '-': ejit_subi(func, EJIT_GPR(0), EJIT_GPR(0), 1); break;
	case '*': ejit_mulr(func, EJIT_GPR(0), EJIT_GPR(0), EJIT_GPR(1)); break;
	case '/': ejit_divr(func, EJIT_GPR(0), EJIT_GPR(0), EJIT_GPR(1)); break;
	default: break;
	}

	/* return accumulator */
	ejit_retr(func, EJIT_GPR(0));

	/* we use GPRs 0 and 1, so 2 in total, no FPRs, and we don't use 64 bit
	 * values (explicitly at least) */
	ejit_compile_func(func, 2, 0, false);
	return func;
}

static int32_t run(struct ejit_func *func)
{
	return ejit_run_func(func, 0, NULL);
}

static void destroy(struct ejit_func *func)
{
	ejit_destroy_func(func);
}

int main()
{
	const char *program = "+ + * - /";
	struct ejit_func *func = compile(program);
	if (!func) {
		fprintf(stderr, "failed to compile program\n");
		return -1;
	}

	int32_t result = run(func);
	printf("%" PRIi32 "\n", result);
	destroy(func);
}