From da6627124bc4bf46d97e43554f6f4d9477accd23 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Sun, 15 Apr 2018 00:05:40 -0400
Subject: [PATCH] A64: Implement SHA1C

---
 src/frontend/A64/decoder/a64.inc             |  2 +-
 src/frontend/A64/translate/impl/simd_sha.cpp | 32 ++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/frontend/A64/decoder/a64.inc b/src/frontend/A64/decoder/a64.inc
index 9a8bb9d2..76131e00 100644
--- a/src/frontend/A64/decoder/a64.inc
+++ b/src/frontend/A64/decoder/a64.inc
@@ -322,7 +322,7 @@ INST(AESMC,                  "AESMC",                                     "01001
 INST(AESIMC,                 "AESIMC",                                    "0100111000101000011110nnnnnddddd")
 
 // Data Processing - FP and SIMD - SHA
-//INST(SHA1C,                  "SHA1C",                                     "01011110000mmmmm000000nnnnnddddd")
+INST(SHA1C,                  "SHA1C",                                     "01011110000mmmmm000000nnnnnddddd")
 //INST(SHA1P,                  "SHA1P",                                     "01011110000mmmmm000100nnnnnddddd")
 //INST(SHA1M,                  "SHA1M",                                     "01011110000mmmmm001000nnnnnddddd")
 INST(SHA1SU0,                "SHA1SU0",                                   "01011110000mmmmm001100nnnnnddddd")
diff --git a/src/frontend/A64/translate/impl/simd_sha.cpp b/src/frontend/A64/translate/impl/simd_sha.cpp
index a5df04db..153a8977 100644
--- a/src/frontend/A64/translate/impl/simd_sha.cpp
+++ b/src/frontend/A64/translate/impl/simd_sha.cpp
@@ -7,6 +7,38 @@
 #include "frontend/A64/translate/impl/impl.h"
 
 namespace Dynarmic::A64 {
+namespace {
+IR::U32 SHAchoose(IREmitter& ir, IR::U32 x, IR::U32 y, IR::U32 z) {
+    return ir.Eor(ir.And(ir.Eor(y, z), x), z);
+}
+}
+
+bool TranslatorVisitor::SHA1C(Vec Vm, Vec Vn, Vec Vd) {
+    IR::U128 x = ir.GetQ(Vd);
+    IR::U32 y = ir.VectorGetElement(32, ir.GetQ(Vn), 0);
+    const IR::U128 w = ir.GetQ(Vm);
+
+    for (size_t i = 0; i < 4; i++) {
+        const IR::U32 low_x = ir.VectorGetElement(32, x, 0);
+        const IR::U32 after_low_x = ir.VectorGetElement(32, x, 1);
+        const IR::U32 before_high_x = ir.VectorGetElement(32, x, 2);
+        const IR::U32 high_x = ir.VectorGetElement(32, x, 3);
+        const IR::U32 t = SHAchoose(ir, after_low_x, before_high_x, high_x);
+        const IR::U32 w_segment = ir.VectorGetElement(32, w, i);
+
+        y = ir.Add(ir.Add(ir.Add(y, ir.RotateRight(low_x, ir.Imm8(27))), t), w_segment);
+        x = ir.VectorSetElement(32, x, 1, ir.RotateRight(after_low_x, ir.Imm8(2)));
+
+        // Move each 32-bit element to the left once
+        // e.g. [3, 2, 1, 0], becomes [2, 1, 0, 3]
+        const IR::U128 shuffled_x = ir.VectorShuffleWords(x, 0b10010011);
+        x = ir.VectorSetElement(32, shuffled_x, 0, y);
+        y = high_x;
+    }
+
+    ir.SetQ(Vd, x);
+    return true;
+}
 
 bool TranslatorVisitor::SHA1SU0(Vec Vm, Vec Vn, Vec Vd) {
     const IR::U128 d = ir.GetQ(Vd);