diff --git a/src/execute.c b/src/execute.c
index f82b97f..4171063 100644
--- a/src/execute.c
+++ b/src/execute.c
@@ -29,7 +29,7 @@ static dword truncateValue(dword value, a64inst_regType regType) {
         return value;
     } else {
         //return value & ~(dword)((1 << WORD_BITS) - 1)
-        return value & (((dword)1 << WORD_BITS) - 1);
+        return value & (dword)(((dword)1 << WORD_BITS) - 1);
     }
 }
 
@@ -67,10 +67,15 @@ static dword readRegister(Machine *state, a64inst_regSpecifier reg, a64inst_regT
     }
 }
 
-// Read from processor register, ensuring that a valid register specifier is given
+// Write to a processor register, ensuring that a valid register specifier is given
 // and truncating the value being written when it can't fit in the specified register.
 static void writeRegister(Machine *state, a64inst_regSpecifier reg, a64inst_regType regType, dword value) {
-    state->registers[reg] = truncateValue(value, regType);
+    assert(reg <= REGISTER_COUNT);
+    if (regType == a64inst_R) {
+        state->registers[reg] = truncateValue(value, regType);
+    } else {
+        *(word*)(state->registers + reg) = (word)truncateValue(value, regType);
+    }
 }
 
 // Updates N and Z condition codes given the machine and a result value
@@ -137,9 +142,10 @@ static void executeDPImmediate(Machine *state, a64inst_instruction *inst) {
         // Execute a wide move data processing instruction
         case a64inst_DPI_WIDEMOV:;
             uint8_t shiftScalar = inst->data.DPImmediateData.processOpData.wideMovData.shiftScalar; 
-            uint16_t wideMovImm = inst->data.DPImmediateData.processOpData.wideMovData.immediate;
+            dword wideMovImm = inst->data.DPImmediateData.processOpData.wideMovData.immediate;
             
             // NOTE: Not checking that shiftScalar has valid value for 32bit registers. Possibly add explicit error.
+            //printf("%x\n", wideMovImm << (shiftScalar * DPI_WIDEMOV_SHIFT) & );
             wideMovImm = truncateValue(wideMovImm << (shiftScalar * DPI_WIDEMOV_SHIFT), regType);
             switch(inst->data.DPImmediateData.processOp) {