Load and execute first instruction

.idea/workspace.xml

@@ -23,40 +23,19 @@
     </configurations>
   </component>
   <component name="ChangeListManager">
-    <list default="true" id="0c3b231e-0637-4ac1-8964-c60fc9e9e691" name="Changes" comment="Gitignore">
+    <list default="true" id="0c3b231e-0637-4ac1-8964-c60fc9e9e691" name="Changes" comment="CPU">
-      <change afterPath="$PROJECT_DIR$/include/rom.h" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/tests/smb.nes" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/rom/CMakeLists.txt" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/rom/ines.c" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/rom/rom.c" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/readme.txt" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/ascii_1.chr" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/ascii_2.chr" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/ascii_3.chr" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/build_rom.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/colors.inc" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/console.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/crc.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/delay.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/devcart.bin" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/macros.inc" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/neshw.inc" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/ppu.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/print.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/shell.inc" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/shell.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/testing.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/common/text_out.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/readme.txt" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/test_cpu_exec_space_apu.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/source/test_cpu_exec_space_ppuio.s" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/test_cpu_exec_space_apu.nes" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/tests/cpu_exec_space/test_cpu_exec_space_ppuio.nes" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/CMakeLists.txt" beforeDir="false" afterPath="$PROJECT_DIR$/CMakeLists.txt" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/cpu/cpu.c" beforeDir="false" afterPath="$PROJECT_DIR$/cpu/cpu.c" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/cpu/cpu.h" beforeDir="false" afterPath="$PROJECT_DIR$/cpu/cpu.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/cpu/memory.c" beforeDir="false" afterPath="$PROJECT_DIR$/cpu/memory.c" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/cpu/op.c" beforeDir="false" afterPath="$PROJECT_DIR$/cpu/op.c" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/cpu/ram.h" beforeDir="false" afterPath="$PROJECT_DIR$/cpu/ram.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/cpu/op.h" beforeDir="false" afterPath="$PROJECT_DIR$/cpu/op.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/include/cpu.h" beforeDir="false" afterPath="$PROJECT_DIR$/include/cpu.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/include/rom.h" beforeDir="false" afterPath="$PROJECT_DIR$/include/rom.h" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/main.c" beforeDir="false" afterPath="$PROJECT_DIR$/main.c" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/rom/ines.c" beforeDir="false" afterPath="$PROJECT_DIR$/rom/ines.c" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/rom/rom.c" beforeDir="false" afterPath="$PROJECT_DIR$/rom/rom.c" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -128,11 +107,6 @@
     </key>
   </component>
   <component name="RunManager" selected="CMake Application.NESEmulator">
-    <configuration default="true" type="CLionExternalRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true">
-      <method v="2">
-        <option name="CLION.EXTERNAL.BUILD" enabled="true" />
-      </method>
-    </configuration>
     <configuration name="NESEmulator" type="CMakeListConfigurationType" factoryName="CMakeListConfigurationFactory" temporary="true">
       <method v="2" />
     </configuration>
@@ -315,6 +289,7 @@
       <workItem from="1700970472703" duration="9613000" />
       <workItem from="1701463001105" duration="2058000" />
       <workItem from="1701558929054" duration="14565000" />
+      <workItem from="1703367277258" duration="1000" />
     </task>
     <task id="LOCAL-00001" summary="Cpu opcodes implementation">
       <option name="closed" value="true" />
@@ -350,15 +325,4 @@
     <MESSAGE value="Gitignore" />
     <option name="LAST_COMMIT_MESSAGE" value="Gitignore" />
   </component>
-  <component name="XDebuggerManager">
-    <breakpoint-manager>
-      <breakpoints>
-        <line-breakpoint enabled="true" type="com.jetbrains.cidr.execution.debugger.OCBreakpointType">
-          <url>file://$PROJECT_DIR$/rom/rom.c</url>
-          <line>32</line>
-          <option name="timeStamp" value="17" />
-        </line-breakpoint>
-      </breakpoints>
-    </breakpoint-manager>
-  </component>
 </project>

cpu/cpu.c

@@ -1,6 +1,7 @@
 #include "../include/cpu.h"
 #include "cpu.h"
 #include "memory.h"
+#include "op.h"
 
 /*
  * =====================================================================================
@@ -24,12 +25,27 @@ CpuRegisters registers;
 Mapper mapper;
 
 void cpu_init() {
-    registers.program_counter = 0x0000;
+    registers.program_counter = 0xc000;
     registers.stack_pointer = 0xff;
     registers.accumulator = 0x00;
     registers.x = 0x00;
     registers.y = 0x00;
     registers.status = 0x00;
+
+    mapper = get_mapper(MAPPER_TYPE_SIMPLE);
+}
+
+void cpu_step() {
+    int i = 0;
+    while (i < 10) {
+        byte op = cpu_get_next_byte();
+        process_op_code(op);
+        i += 1;
+    }
+}
+
+void cpu_add_cycles(unsigned int cycle_count) {
+
 }
 
 // === Registers ===

cpu/cpu.h

@@ -58,4 +58,6 @@ void cpu_stack_push_context();
 byte cpu_stack_pop();
 void cpu_stack_pop_context();
 
+void cpu_add_cycles(unsigned int cycle_count);
+
 #endif //CPU_CPU_H

cpu/memory.c

@@ -4,15 +4,30 @@
 
 #include "memory.h"
 #include "ram.h"
+#include "../include/rom.h"
 
 byte mem_get_byte(Mapper *mapper, address addr) {
     address redirected_addr = mapper->redirect_addr(addr);
-    return ram_get_byte(redirected_addr);
+
+    if (redirected_addr < 0x0800) {
+        return ram_get_byte(redirected_addr);
+    } else if (redirected_addr >= 0x4020) {
+        return rom_prg_get_byte(redirected_addr - 0x4020);
+    }
+
+    return 0;
 }
 
 word mem_get_word(Mapper *mapper, address addr) {
     address redirected_addr = mapper->redirect_addr(addr);
-    return ram_get_word(redirected_addr);
+
+    if (redirected_addr < 0x0800) {
+        return ram_get_word(redirected_addr);
+    } else if (redirected_addr >= 0x4020) {
+        return rom_prg_get_word(redirected_addr - 0x4020);
+    }
+
+    return 0;
 }
 
 void mem_set_byte(Mapper *mapper, address addr, byte byte) {

cpu/op.c

@@ -10,7 +10,7 @@
 
 #define IS_OP_CODE_MODE(op, op_code, addr_mode) \
     case op_code:                               \
-        log_debug("OP: %s", "op");                \
+        log_debug("OP: %s", #op);                \
         op_ ## op(ADDR_MODE_ ## addr_mode);     \
         break;
 
@@ -809,7 +809,7 @@ void op_XAA(AddressingMode addr_mode) {
     assert(false);
 }
 
-void process_op_code(int op) {
+void process_op_code(byte op) {
     switch (op) {
         // CTRL
         IS_OP_CODE(BRK, 0x00)

cpu/op.h

@@ -1,3 +1,5 @@
+#include "../include/cpu.h"
+
 #ifndef CPU_OP_H
 #define CPU_OP_H
 
@@ -31,4 +33,6 @@ typedef enum {
     ADDR_MODE_ZERO_PAGE_INDEXED_Y,  // d,y
 } AddressingMode;
 
+void process_op_code(byte op);
+
 #endif

include/cpu.h

@@ -23,11 +23,7 @@ typedef unsigned char byte;
 typedef unsigned short address;
 typedef unsigned short word;
 
-/**
+void cpu_init();
- * @brief Set clock
+void cpu_step();
- */
-void cpu_step_to(int cycle);
-
-void cpu_add_cycles(int count);
 
 #endif

include/rom.h

@@ -5,12 +5,25 @@
 #ifndef NESEMULATOR_ROM_H
 #define NESEMULATOR_ROM_H
 
+// The size of the header in a ROM file, in bytes
+#include "cpu.h"
+
+#define ROM_HEADER_SIZE 16
+// The size of the trainer in a ROM file, in bytes
+#define ROM_TRAINER_SIZE 512
+
 typedef struct {
-    char* prg_rom;
+    byte *prg_rom;
-    char* chr_rom;
+    byte *chr_rom;
-    void* header;
+    void *header;
 } Rom;
 
-int read_rom(char* path);
+int rom_load(char *path);
+
+void rom_uninit();
+
+byte rom_prg_get_byte(address addr);
+
+word rom_prg_get_word(address addr);
 
 #endif //NESEMULATOR_ROM_H

main.c

@@ -20,8 +20,14 @@
 #include "include/rom.h"
 
 int main() {
-    char *rom_path = "../tests/cpu_exec_space/test_cpu_exec_space_ppuio.nes";
+    char *rom_path = "../tests/smb.nes";
-    read_rom(rom_path);
+
+    cpu_init();
+    rom_load(rom_path);
+
+    cpu_step();
+
+    rom_uninit();
 
     return EXIT_SUCCESS;
 }

rom/ines.c

@@ -110,31 +110,60 @@ INesHeader read_header(const char header_buf[16]) {
     return header;
 }
 
-bool rom_nes_read(const char header_buf[16], FILE *file, Rom *rom) {
+bool rom_ines_read_trainer(FILE *file, INesHeader *header) {
-    INesHeader header = read_header(header_buf);
+    if (!header->flags.has_trainer) {
-    rom->header = &header;
+        log_debug("ROM does not contains trainer");
-
+        return true;
-    // We don't support the trainer, so we skip ahead by 512 bytes if needed.
-    if (header.flags.has_trainer && !fseek(file, 512, SEEK_CUR)) {
-        perror("Failed to seek ahead of trainer ROM section");
-        return false;
     }
 
-    unsigned int prg_rom_size = header.prg_rom_size * 16384;
+    // We don't support the trainer, so we skip ahead instead.
+    if (fseek(file, ROM_TRAINER_SIZE, SEEK_CUR)) {
+        log_debug("ROM has trainer, skipping %d bytes", ROM_TRAINER_SIZE);
+        return true;
+    }
+
+    log_error("Failed to skip trainer");
+    return false;
+}
+
+bool rom_ines_read_prg_rom(FILE *file, INesHeader *header, Rom *rom) {
+    unsigned int prg_rom_size = header->prg_rom_size * 16384;
     rom->prg_rom = (char *) malloc(prg_rom_size * sizeof(char));
-    if (fread(rom->prg_rom, sizeof(char), prg_rom_size, file) < prg_rom_size) {
-        perror("Failed to read PRG ROM");
-        return false;
-    }
 
-    if (header.chr_rom_size > 0) {
+    log_debug("Reading %d bytes PRG ROM", prg_rom_size);
-        unsigned int chr_rom_size = header.chr_rom_size * 8192;
+
-        rom->chr_rom = (char *) malloc(chr_rom_size * sizeof(char));
+    if (fread(rom->prg_rom, sizeof(char), prg_rom_size, file) < prg_rom_size) {
-        if (fread(rom->chr_rom, sizeof(char), chr_rom_size, file) < chr_rom_size) {
+        log_error("Failed to read PRG ROM");
-            perror("Failed to read CHR ROM");
+        return false;
-            return false;
-        }
     }
 
     return true;
 }
+
+bool rom_ines_read_chr_rom(FILE *file, INesHeader *header, Rom *rom) {
+    if (header->chr_rom_size <= 0) {
+        log_debug("No CHR ROM to read");
+        return true;
+    }
+
+    unsigned int chr_rom_size = header->chr_rom_size * 8192;
+    rom->chr_rom = (char *) malloc(chr_rom_size * sizeof(char));
+
+    log_debug("Reading %d bytes CHR ROM", chr_rom_size);
+
+    if (fread(rom->chr_rom, sizeof(char), chr_rom_size, file) < chr_rom_size) {
+        log_error("Failed to read CHR ROM");
+        return false;
+    }
+
+    return true;
+}
+
+bool rom_ines_read(const char header_buf[ROM_HEADER_SIZE], FILE *file, Rom *rom) {
+    INesHeader header = read_header(header_buf);
+    rom->header = &header;
+
+    return rom_ines_read_trainer(file, &header) &&
+           rom_ines_read_prg_rom(file, &header, rom) &&
+           rom_ines_read_chr_rom(file, &header, rom);
+}

rom/rom.c

@@ -4,51 +4,73 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <assert.h>
 
 #include "../include/rom.h"
 #include "ines.c"
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
-void rom_init(Rom *rom) {
+Rom rom;
-    rom->header = NULL;
+
-    rom->prg_rom = NULL;
+void rom_init() {
-    rom->chr_rom = NULL;
+    rom.header = NULL;
+    rom.prg_rom = NULL;
+    rom.chr_rom = NULL;
 }
 
-void rom_uninit(Rom *rom) {
+int rom_load(char *path) {
-    free(rom->prg_rom);
+    rom_init();
-    free(rom->chr_rom);
-}
 
-int read_rom(char *path) {
     FILE *file = fopen(path, "r");
     if (!file) {
-        perror("Failed to open ROM");
+        log_error("Failed to open ROM");
         return EXIT_FAILURE;
     }
 
-    char header_buffer[16] = {0};
+    char header_buffer[ROM_HEADER_SIZE] = {0};
     size_t read_size = fread(header_buffer, sizeof(char), ARRAY_SIZE(header_buffer), file);
     if (read_size < ARRAY_SIZE(header_buffer)) {
-        perror("Failed to read ROM");
+        log_error("Failed to read ROM");
         return EXIT_FAILURE;
     }
 
     if (!rom_is_ines(header_buffer)) {
-        perror("Only iNes ROMs are supported");
+        log_error("Only iNes ROMs are supported");
         return EXIT_FAILURE;
     }
 
-    Rom rom;
+    log_info("Reading iNes 1.0 ROM at %s", path);
-    rom_init(&rom);
+    rom_ines_read(header_buffer, file, &rom);
-    rom_nes_read(header_buffer, file, &rom);
-    rom_uninit(&rom);
 
     if (fclose(file) != 0) {
-        perror("Failed to close ROM file");
+        log_error("Failed to close ROM file");
         return EXIT_FAILURE;
     }
 
     return 0;
 }
+
+void rom_uninit() {
+    assert(rom.prg_rom != NULL);
+    assert(rom.chr_rom != NULL);
+
+    free(rom.prg_rom);
+    free(rom.chr_rom);
+    
+    log_info("Cleared ROM data");
+}
+
+byte rom_prg_get_byte(address addr) {
+    assert(rom.prg_rom != NULL);
+
+    return rom.prg_rom[addr];
+}
+
+word rom_prg_get_word(address addr) {
+    assert(rom.prg_rom != NULL);
+
+    word word = rom.prg_rom[addr];
+    word += rom.prg_rom[addr + 1] << 8;    // Little endian
+    return word;
+}