multiply/data transfer

emulate.c

@@ -335,6 +335,66 @@ void branchInstr(struct ProcessorState *processor, uint32_t address)
   return;
 }
 
+void multiplyInstr(struct ProcessorState *processor, uint32_t instruction)
+{
+  // Check if the instruction should be executed according to its condition codes
+  if(!validCond(getBits(instruction, 28, 31), processor)){
+    return;
+  }
+
+  //TODO: check if this is correct
+  if(isSet(instruction, 21)){
+    // Execute multiply and accumulate 
+    uint32_t result = ((getBits(instruction, 0, 3))*(getBits(instruction, 8, 11)))+(getBits(instruction, 12, 15));
+  } else {
+    uint32_t result = (getBits(instruction, 0, 3))*(getBits(instruction, 8, 11));
+  }
+
+  // Store the result
+  &processor->registers[getBits(instruction, 16, 19)] = result;
+
+  // Set the CPRS flags
+  if(isSet(instruction, 20)){
+    uint32_t *cprs = processor->registers[16];
+    // N
+    setBit(cprs, 31, isSet(result, 31));
+    // Z
+    setBit(cprs, 30, result == 0);
+  }
+}
+
+void dataTransferInstr(struct ProcessorState *processor, uint32_t instruction)
+{
+  // Check if instruction should be executed according to its condition codes
+  if(!validCond(getBits(instruction, 28, 31), processor)){
+    return;
+  }
+
+  // Get the offset
+  bool carry;
+  uint32_t offset = barrelShift(!isSet(instruction, 25), getBits(instruction, 0, 11), &carry, processor);
+
+  //TODO: check if this is correct
+  if(isSet(instruction, 20)){
+    // Load from memory - memory address stored in base register is to be accessed and loaded into the destination register
+    &processor->registers[getBits(instruction, 12, 15)] = processor->memory[getBits(instruction, 16, 19)];
+  } else {
+    // Store into memory - source register is to be stored at the memory address stored in the base register
+    processor->memory[getBits(instruction, 16, 19)] = processor->registers[getBits(instruction, 12, 15)];
+  }
+
+  // Post Indexing, must happen after transfer
+  if(!isSet(instruction, 24)){
+    if(isSet(instruction, 23)){
+      uint32_t baseReg = (getBits(instruction, 16, 19))+offset;
+    } else {
+      uint32_t baseReg = (getBits(instruction, 16, 19))-offset;
+    }
+    // Store new base register
+    &processor->registers[getBits(instruction, 16, 19)] = baseReg;
+  }
+}
+
 // Steps through pipeline calling appropriate instruction method.
 // Sets teminate if instruction is all-0.
 void step(struct ProcessorState *processor, bool *terminate)