move stuff around and create initial source structure

1 files changed, 134 insertions, 0 deletions

diff --git a/src/emu/risci.c b/src/emu/risci.c
new file mode 100644
index 0000000..8c4e30f
--- /dev/null
+++ b/src/emu/risci.c
@@ -0,0 +1,134 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <readline/readline.h>
+
+#include "asm.h"
+#include "cpu.h"
+#include "log.h"
+#include "opc.h"
+
+bool is_debug = false;
+bool is_interactive = false;
+
+/* global program buffer */
+uint8_t *P = NULL;
+
+static
+void usage(int rc)
+{
+	fprintf(stderr, "Usage: risci [-dhi] <program>\n");
+	exit(rc);
+}
+
+static
+void signal_handler(int sig)
+{
+	switch (sig) {
+	case SIGILL:
+		/* SIGILL is raised by the cpu for an unknown instruction */
+		error("ERROR: illegal instruction.");
+		if (!is_interactive)
+			exit(-1);
+		break;
+	case SIGSEGV:
+		/* SIGSEGV is raised for unaligned memory access */
+		error("ERROR: unaligned memory access.");
+		if (!is_interactive)
+			exit(-1);
+		break;
+	case SIGFPE:
+		/* SIGFPE is raised by devision with zero */
+		error("ERROR: division by zero.");
+		exit(-1);
+		break;
+	}
+}
+
+static
+void read_program(const char *program)
+{
+	struct stat sb;
+	if (lstat(program, &sb) == -1)
+		pdie("cannot stat program");
+
+	if (sb.st_size % sizeof(uint32_t))
+		die("program does not align to op-code size of %u bytes", sizeof(uint32_t));
+
+	int pfd;
+	if ((pfd = open(program, O_RDONLY)) == -1)
+		pdie("could not open program");
+
+	P = malloc(sb.st_size + sizeof(uint32_t));
+	if (read(pfd, P, sb.st_size) != sb.st_size)
+		die("premature end of program");
+
+	memset(P + sb.st_size, 0xFF, sizeof(uint32_t));
+}
+
+static
+uint32_t next_instruction(void)
+{
+	if (is_interactive) {
+		/* read next instruction from stdin */
+		printf("%03d", PC/4);
+		return compile(readline("> "));
+	}
+
+	uint32_t tmp;
+	memcpy(&tmp, &P[PC], sizeof(uint32_t));
+	return tmp;
+}
+
+int main(int argc, char *argv[])
+{
+	int ch;
+
+	while ((ch = getopt(argc, argv, "dhi")) != -1) {
+		switch (ch) {
+		case 'd':
+			is_debug = true;
+			break;
+		case 'h':
+			usage(EXIT_SUCCESS);
+		case 'i':
+			is_interactive = true;
+			break;
+		case '?':
+		default:
+			usage(EXIT_FAILURE);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	/* catch cpu signal traps */
+	signal(SIGILL,  signal_handler);
+	signal(SIGFPE,  signal_handler);
+	signal(SIGSEGV, signal_handler);
+
+	/* load program from file if we're not in interactive mode */
+	if (!is_interactive) {
+		if (argc < 1)
+			usage(EXIT_FAILURE);
+
+		read_program(argv[0]);
+	}
+
+	/* reset program counter to first instruction */
+	PC = 0;
+
+	/* start instruction loop */
+	while (1) {
+		execute(next_instruction());
+		PC += 4;
+	}
+
+	/* not reached, program is terminated by signal traps from the cpu */
+}