calculator works on constant string

2 files changed, 64 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..27fe68e
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,62 @@
+#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);
+}
diff --git a/src/source.mk b/src/source.mk
new file mode 100644
index 0000000..5b2c0e3
--- /dev/null
+++ b/src/source.mk
@@ -0,0 +1,2 @@
+SRCS		!= echo src/*.c
+CALC_SOURCES	+= $(SRCS)