From f981835e44e17a58c438a53a1ae32de7de3273c2 Mon Sep 17 00:00:00 2001
From: Stefan Arentz <stefan@arentz.ca>
Date: Mon, 21 Nov 2016 20:47:27 -0500
Subject: [PATCH] Fixes #31 - Allow RAM images to be loaded from disk

---
 cpu.c | 34 +++++++++++++++++++++++++++++++++-
 cpu.h |  4 +++-
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/cpu.c b/cpu.c
index 8313f74..e438f6a 100644
--- a/cpu.c
+++ b/cpu.c
@@ -221,9 +221,13 @@ static void _ram_write(struct cpu_t *cpu, struct mem_t *mem, uint16_t addr, uint
 }
 
 void cpu_add_ram(struct cpu_t *cpu, uint16_t start, uint16_t length) {
+   cpu_add_ram_data(cpu, start, length, calloc(length, 0x01));
+}
+
+void cpu_add_ram_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_RAM;
-  mem->obj = malloc(length);
+  mem->obj = data;
   mem->start = start;
   mem->length = length;
   mem->read_handler = _ram_read;
@@ -232,6 +236,34 @@ void cpu_add_ram(struct cpu_t *cpu, uint16_t start, uint16_t length) {
   cpu_add_mem(cpu, mem);
 }
 
+void cpu_add_ram_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_ram_data(cpu, start, file_info.st_size, (uint8_t*) data);
+}
+
 // ROM Memory
 
 static uint8_t _rom_read(struct cpu_t *cpu, struct mem_t *mem, uint16_t addr) {
diff --git a/cpu.h b/cpu.h
index 488cd59..aca5a28 100644
--- a/cpu.h
+++ b/cpu.h
@@ -83,8 +83,10 @@ void cpu_shutdown(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_file(struct cpu_t *cpu, uint16_t start, char *path);
+void cpu_add_ram_data(struct cpu_t *cpu, uint16_t start, uint16_t length, uint8_t *data);
+void cpu_add_ram_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_rom_file(struct cpu_t *cpu, uint16_t start, char *path);
 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_strict(struct cpu_t *cpu, bool strict);