Sean Flannigan - Computer-Architecture

README.md

@@ -1,3 +1,4 @@
+<!-- https://github.com/LambdaSchool/Computer-Architecture/pull/199 -->
 # Computer Architecture
 
 ## Project

ls8/cpu.c

@@ -26,6 +26,16 @@ void cpu_load(struct cpu *cpu)
   // TODO: Replace this with something less hard-coded
 }
 
+// MAR - memory address register | where does is go
+// MDR - memory data register | what it is
+void cpu_ram_write(struct cpu *cpu, unsigned char mar, unsigned char mdr) {
+  cpu->ram[mar] = mdr;
+}
+
+unsigned char cpu_ram_read(struct cpu *cpu, unsigned char mar) {
+  return cpu->ram[mar];
+}
+
 /**
  * ALU
  */
@@ -64,4 +74,15 @@ void cpu_run(struct cpu *cpu)
 void cpu_init(struct cpu *cpu)
 {
   // TODO: Initialize the PC and other special registers
+  // set r0-r6 to clear to 0
+  for (int i = 0; i < 7; i++) {
+    cpu->reg[i] = 0;
+  }
+  // set r7 to 0xF4
+  cpu->reg[7] = 0xF4;
+  // set PC to 0 | no flags yet
+  cpu->PC = 0;
+  // set ram to 0
+  memset(cpu->ram, 0, sizeof cpu->ram);
+
 }

ls8/cpu.h

@@ -5,8 +5,11 @@
 struct cpu {
   // TODO
   // PC
+  unsigned char PC;
   // registers (array)
+  unsigned char reg[8];
   // ram (array)
+  unsigned char ram[256];
 };
 
 // ALU operations