Kevin Sooter - Computer-Architecture

README.md

@@ -2,11 +2,12 @@
 
 ## Project
 
-* [Implement the LS-8 Emulator](ls8/)
+- [Implement the LS-8 Emulator](ls8/)
 
 ## Task List: add this to the first comment of your Pull Request
 
 ### Day 1: Get `print8.ls8` running
+
 - [ ] Inventory what is here
 - [ ] Implement `struct cpu` in `cpu.h`
 - [ ] Add RAM functions `cpu_ram_read` and `cpu_ram_write`
@@ -17,15 +18,18 @@
 - [ ] Add the `PRN` instruction
 
 ### Day 2: Add the ability to load files dynamically, get `mult.ls8` and `stack.ls8` running
+
 - [ ] Un-hardcode the machine code
 - [ ] Implement the `cpu_load` function to load an `.ls8` file given the filename passed in as an argument
 - [ ] Implement a Multiply instruction and Print the result (run `mult8.ls8`)
 - [ ] Implement the System Stack and be able to run the `stack.ls8` program
 
 ### Day 3: Get `call.ls8` running
+
 - [ ] Implement the CALL and RET instructions
 - [ ] Implement Subroutine Calls and be able to run the `call.ls8` program
 
 ### Stretch
+
 - [ ] Add the timer interrupt to the LS-8 emulator
 - [ ] Add the keyboard interrupt to the LS-8 emulator

ls8/cpu.c

@@ -8,33 +8,45 @@
 void cpu_load(struct cpu *cpu)
 {
   char data[DATA_LEN] = {
-    // From print8.ls8
-    0b10000010, // LDI R0,8
-    0b00000000,
-    0b00001000,
-    0b01000111, // PRN R0
-    0b00000000,
-    0b00000001  // HLT
+      // From print8.ls8
+      0b10000010, // LDI R0,8
+      0b00000000,
+      0b00001000,
+      0b01000111, // PRN R0
+      0b00000000,
+      0b00000001 // HLT
   };
 
   int address = 0;
 
-  for (int i = 0; i < DATA_LEN; i++) {
+  for (int i = 0; i < DATA_LEN; i++)
+  {
     cpu->ram[address++] = data[i];
   }
 
   // TODO: Replace this with something less hard-coded
 }
 
+unsigned char cpu_ram_read(struct cpu *cpu, unsigned char address)
+{
+  return cpu->ram[address];
+}
+
+void cpu_ram_write(struct cpu *cpu, unsigned char address, unsigned char value)
+{
+  cpu->ram[address] = value;
+}
+
 /**
  * ALU
  */
 void alu(struct cpu *cpu, enum alu_op op, unsigned char regA, unsigned char regB)
 {
-  switch (op) {
-    case ALU_MUL:
-      // TODO
-      break;
+  switch (op)
+  {
+  case ALU_MUL:
+    // TODO
+    break;
 
     // TODO: implement more ALU ops
   }
@@ -47,7 +59,8 @@ void cpu_run(struct cpu *cpu)
 {
   int running = 1; // True until we get a HLT instruction
 
-  while (running) {
+  while (running)
+  {
     // TODO
     // 1. Get the value of the current instruction (in address PC).
     // 2. Figure out how many operands this next instruction requires

ls8/cpu.h

@@ -2,27 +2,34 @@
 #define _CPU_H_
 
 // Holds all information about the CPU
-struct cpu {
+struct cpu
+{
   // TODO
   // PC
+  unsigned char PC;
+
   // registers (array)
+  unsigned char registers[8];
+
   // ram (array)
+  unsigned char ram[256];
 };
 
 // ALU operations
-enum alu_op {
-	ALU_MUL
-	// Add more here
+enum alu_op
+{
+  ALU_MUL
+  // Add more here
 };
 
 // Instructions
 
 // These use binary literals. If these aren't available with your compiler, hex
 // literals should be used.
 
-#define LDI  0b10000010
-#define HLT  0b00000001
-#define PRN  0b01000111
+#define LDI 0b10000010
+#define HLT 0b00000001
+#define PRN 0b01000111
 // TODO: more instructions here. These can be used in cpu_run().
 
 // Function declarations