diff --git a/src/core/cpu/arm/data_processing.zig b/src/core/cpu/arm/data_processing.zig
index 7bc3f44..d8ce6e0 100644
--- a/src/core/cpu/arm/data_processing.zig
+++ b/src/core/cpu/arm/data_processing.zig
@@ -62,7 +62,9 @@ pub fn dataProcessing(comptime I: bool, comptime S: bool, comptime kind: u4) Ins
                     if (rd == 0xF)
                         return undefinedTestBehaviour(cpu);
 
-                    overflow = @addWithOverflow(u32, op1, op2, &result);
+                    const tmp = @addWithOverflow(op1, op2);
+                    result = tmp[0];
+                    overflow = tmp[1] == 0b1;
                 },
                 0xC => result = op1 | op2, // ORR
                 0xD => result = op2, // MOV
@@ -163,18 +165,18 @@ pub fn sbc(left: u32, right: u32, old_carry: u1) u32 {
 }
 
 pub fn add(overflow: *bool, left: u32, right: u32) u32 {
-    var ret: u32 = undefined;
-    overflow.* = @addWithOverflow(u32, left, right, &ret);
-    return ret;
+    const ret = @addWithOverflow(left, right);
+    overflow.* = ret[1] == 0b1;
+
+    return ret[0];
 }
 
 pub fn adc(overflow: *bool, left: u32, right: u32, old_carry: u1) u32 {
-    var ret: u32 = undefined;
-    const first = @addWithOverflow(u32, left, right, &ret);
-    const second = @addWithOverflow(u32, ret, old_carry, &ret);
+    const tmp = @addWithOverflow(left, right);
+    const ret = @addWithOverflow(tmp[0], old_carry);
+    overflow.* = (tmp[1] | ret[1]) == 0b1;
 
-    overflow.* = first or second;
-    return ret;
+    return ret[0];
 }
 
 fn undefinedTestBehaviour(cpu: *Arm7tdmi) void {
diff --git a/src/core/cpu/thumb/alu.zig b/src/core/cpu/thumb/alu.zig
index 778da99..43c43e7 100644
--- a/src/core/cpu/thumb/alu.zig
+++ b/src/core/cpu/thumb/alu.zig
@@ -34,7 +34,12 @@ pub fn fmt4(comptime op: u4) InstrFn {
                 0x8 => result = op1 & op2, // TST
                 0x9 => result = 0 -% op2, // NEG
                 0xA => result = op1 -% op2, // CMP
-                0xB => overflow = @addWithOverflow(u32, op1, op2, &result), // CMN
+                0xB => {
+                    // CMN
+                    const tmp = @addWithOverflow(op1, op2);
+                    result = tmp[0];
+                    overflow = tmp[1] == 0b1;
+                },
                 0xC => result = op1 | op2, // ORR
                 0xD => result = @truncate(u32, @as(u64, op2) * @as(u64, op1)),
                 0xE => result = op1 & ~op2,