From: Jacob Lifshay <programmerjake@gmail.com>
Date: Thu, 3 Sep 2020 23:20:16 +0000 (-0700)
Subject: fix subfc* to calculate correct carries
X-Git-Tag: v0.2.0~23
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e785e6b812224af1b2ce40d55c29e73dc3591531;p=power-instruction-analyzer.git

fix subfc* to calculate correct carries
---

diff --git a/src/instr_models.rs b/src/instr_models.rs
index e56e4fb..d140ea5 100644
--- a/src/instr_models.rs
+++ b/src/instr_models.rs
@@ -111,8 +111,8 @@ pub fn subfco(inputs: InstructionInput) -> InstructionResult {
     let (result, ov) = rb.overflowing_sub(ra);
     let result = result as u64;
     let ov32 = (rb as i32).overflowing_sub(ra as i32).1;
-    let ca = (rb as u64).overflowing_sub(ra as u64).1;
-    let ca32 = (rb as u32).overflowing_sub(ra as u32).1;
+    let ca = !(rb as u64).overflowing_sub(ra as u64).1;
+    let ca32 = !(rb as u32).overflowing_sub(ra as u32).1;
     Ok(InstructionOutput {
         rt: Some(result),
         overflow: Some(propagate_so(OverflowFlags { so: ov, ov, ov32 }, inputs)?),