From 6e0eaaa5be9bf8ded632007a88629c3ae13cfd02 Mon Sep 17 00:00:00 2001
From: Stefan Arentz <stefan@arentz.ca>
Date: Wed, 16 Nov 2016 15:28:35 -0500
Subject: [PATCH] Fixes #19 - Allow ROM regions to be loaded from files

---
 cpu.c | 33 +++++++++++++++++++++++++++++++--
 cpu.h |  3 ++-
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/cpu.c b/cpu.c
index cc0f3a0..b3795a6 100644
--- a/cpu.c
+++ b/cpu.c
@@ -21,13 +21,14 @@
 // SOFTWARE.
 
 #include <assert.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdint.h>
 #include <inttypes.h>
 #include <stdlib.h>
 #include <unistd.h>
-
+#include <sys/stat.h>
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 
@@ -351,7 +352,7 @@ static uint8_t _rom_read(struct cpu_t *cpu, struct mem_t *mem, uint16_t addr) {
   return ((uint8_t*) mem->obj)[addr - mem->start];
 }
 
-void cpu_add_rom(struct cpu_t *cpu, uint16_t start, uint16_t length, uint8_t *data) {
+void cpu_add_rom_data(struct cpu_t *cpu, uint16_t start, uint16_t length, uint8_t *data) {
   struct mem_t *mem = (struct mem_t*) malloc(sizeof(struct mem_t));
   mem->type = MEM_TYPE_ROM;
   mem->obj = data;
@@ -363,6 +364,34 @@ void cpu_add_rom(struct cpu_t *cpu, uint16_t start, uint16_t length, uint8_t *da
   cpu_add_mem(cpu, mem);
 }
 
+void cpu_add_rom_file(struct cpu_t *cpu, uint16_t start, char *path) {
+   int fd = open(path, O_RDONLY);
+   if (fd == -1) {
+      return;
+   }
+
+   struct stat file_info;
+   if (fstat(fd, &file_info) == -1) {
+      close(fd);
+      return;
+   }
+
+   if (file_info.st_size  > (64 * 1024 - start)) {
+      close(fd);
+      return;
+   }
+
+   char *data = malloc(file_info.st_size);
+   if (read(fd, data, file_info.st_size) != file_info.st_size) {
+      close(fd);
+      return;
+   }
+
+   close(fd);
+
+   cpu_add_rom_data(cpu, start, file_info.st_size, (uint8_t*) data);
+}
+
 // IO Memory
 
 void cpu_add_iom(struct cpu_t *cpu, uint16_t start, uint16_t length, void *obj, mem_read_handler_t read_handler, mem_write_handler_t write_handler) {
diff --git a/cpu.h b/cpu.h
index 15cd995..d889f64 100644
--- a/cpu.h
+++ b/cpu.h
@@ -73,7 +73,8 @@ void cpu_init(struct cpu_t *cpu);
 
 void cpu_add_mem(struct cpu_t *cpu, struct mem_t *mem);
 void cpu_add_ram(struct cpu_t *cpu, uint16_t start, uint16_t length);
-void cpu_add_rom(struct cpu_t *cpu, uint16_t start, uint16_t length, uint8_t *data);
+void cpu_add_rom_file(struct cpu_t *cpu, uint16_t start, char *path);
+void cpu_add_rom_data(struct cpu_t *cpu, uint16_t start, uint16_t length, uint8_t *data);
 void cpu_add_iom(struct cpu_t *cpu, uint16_t start, uint16_t length, void *obj, mem_read_handler_t read_handler, mem_write_handler_t write_handler);
 
 void cpu_trace(struct cpu_t *cpu, uint8_t trace);