From 121bf93cbe2c23fe0a47f1f43e3f050df46e976d Mon Sep 17 00:00:00 2001
From: Wunkolo <Wunkolo@gmail.com>
Date: Mon, 17 Apr 2023 10:33:37 -0700
Subject: [PATCH] [PPC] Implement `vsubcuw`

Other half of #2125. I don't know of any title that utilizes this instruction, but I went ahead and implemented it for completeness.

Verified the implementation with `instr__gen_vsubcuw` from #1348. Can be grabbed with:
```
git checkout origin/gen_tests -- src\xenia\cpu\ppc\testing\*vsubcuw.s
```
---
 src/xenia/cpu/ppc/ppc_emit_altivec.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/xenia/cpu/ppc/ppc_emit_altivec.cc b/src/xenia/cpu/ppc/ppc_emit_altivec.cc
index b8257c1bc..437b3f09b 100644
--- a/src/xenia/cpu/ppc/ppc_emit_altivec.cc
+++ b/src/xenia/cpu/ppc/ppc_emit_altivec.cc
@@ -1662,7 +1662,11 @@ int InstrEmit_vsrw128(PPCHIRBuilder& f, const InstrData& i) {
 }
 
 int InstrEmit_vsubcuw(PPCHIRBuilder& f, const InstrData& i) {
-  XEINSTRNOTIMPLEMENTED();
+  Value* underflow =
+      f.VectorCompareUGE(f.LoadVR(i.VX.VA), f.LoadVR(i.VX.VB), INT32_TYPE);
+  Value* borrow =
+      f.VectorShr(underflow, f.LoadConstantVec128(vec128i(31)), INT32_TYPE);
+  f.StoreVR(i.VX.VD, borrow);
   return 1;
 }