From ca903c15857b093e538bad823fdd080959889d00 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Thu, 19 Apr 2018 07:40:02 -0400
Subject: [PATCH] A64: Implement SHA256H and SHA256H2

---
 src/frontend/A64/decoder/a64.inc             |  4 +-
 src/frontend/A64/translate/impl/simd_sha.cpp | 73 ++++++++++++++++++++
 2 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/src/frontend/A64/decoder/a64.inc b/src/frontend/A64/decoder/a64.inc
index 8fa17bd8..ec63a568 100644
--- a/src/frontend/A64/decoder/a64.inc
+++ b/src/frontend/A64/decoder/a64.inc
@@ -326,8 +326,8 @@ INST(SHA1C,                  "SHA1C",                                     "01011
 INST(SHA1P,                  "SHA1P",                                     "01011110000mmmmm000100nnnnnddddd")
 INST(SHA1M,                  "SHA1M",                                     "01011110000mmmmm001000nnnnnddddd")
 INST(SHA1SU0,                "SHA1SU0",                                   "01011110000mmmmm001100nnnnnddddd")
-//INST(SHA256H,                "SHA256H",                                   "01011110000mmmmm010000nnnnnddddd")
-//INST(SHA256H2,               "SHA256H2",                                  "01011110000mmmmm010100nnnnnddddd")
+INST(SHA256H,                "SHA256H",                                   "01011110000mmmmm010000nnnnnddddd")
+INST(SHA256H2,               "SHA256H2",                                  "01011110000mmmmm010100nnnnnddddd")
 INST(SHA256SU1,              "SHA256SU1",                                 "01011110000mmmmm011000nnnnnddddd")
 INST(SHA1H,                  "SHA1H",                                     "0101111000101000000010nnnnnddddd")
 INST(SHA1SU1,                "SHA1SU1",                                   "0101111000101000000110nnnnnddddd")
diff --git a/src/frontend/A64/translate/impl/simd_sha.cpp b/src/frontend/A64/translate/impl/simd_sha.cpp
index 3d3f3bce..324fc90e 100644
--- a/src/frontend/A64/translate/impl/simd_sha.cpp
+++ b/src/frontend/A64/translate/impl/simd_sha.cpp
@@ -47,6 +47,67 @@ IR::U128 SHA1HashUpdate(IREmitter& ir, Vec Vm, Vec Vn, Vec Vd, SHA1HashUpdateFun
 
     return x;
 }
+
+IR::U32 SHAhashSIGMA0(IREmitter& ir, IR::U32 x) {
+    const IR::U32 tmp1 = ir.RotateRight(x, ir.Imm8(2));
+    const IR::U32 tmp2 = ir.RotateRight(x, ir.Imm8(13));
+    const IR::U32 tmp3 = ir.RotateRight(x, ir.Imm8(22));
+
+    return ir.Eor(tmp1, ir.Eor(tmp2, tmp3));
+}
+
+IR::U32 SHAhashSIGMA1(IREmitter& ir, IR::U32 x) {
+    const IR::U32 tmp1 = ir.RotateRight(x, ir.Imm8(6));
+    const IR::U32 tmp2 = ir.RotateRight(x, ir.Imm8(11));
+    const IR::U32 tmp3 = ir.RotateRight(x, ir.Imm8(25));
+
+    return ir.Eor(tmp1, ir.Eor(tmp2, tmp3));
+}
+
+enum class SHA256HashPart {
+    Part1,
+    Part2
+};
+
+IR::U128 SHA256hash(IREmitter& ir, IR::U128 x, IR::U128 y, IR::U128 w, SHA256HashPart part) {
+    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 low_y = ir.VectorGetElement(32, y, 0);
+        const IR::U32 after_low_y = ir.VectorGetElement(32, y, 1);
+        const IR::U32 before_high_y = ir.VectorGetElement(32, y, 2);
+        const IR::U32 high_y = ir.VectorGetElement(32, y, 3);
+
+        const IR::U32 choice = SHAchoose(ir, low_y, after_low_y, before_high_y);
+        const IR::U32 majority = SHAmajority(ir, low_x, after_low_x, before_high_x);
+
+        const IR::U32 t = [&] {
+            const IR::U32 w_element = ir.VectorGetElement(32, w, i);
+            const IR::U32 sig = SHAhashSIGMA1(ir, low_y);
+
+            return ir.Add(high_y, ir.Add(sig, ir.Add(choice, w_element)));
+        }();
+
+        const IR::U32 new_low_x = ir.Add(t, ir.Add(SHAhashSIGMA0(ir, low_x), majority));
+        const IR::U32 new_low_y = ir.Add(t, high_x);
+
+        // Shuffle all words left by 1 element: [3, 2, 1, 0] -> [2, 1, 0, 3]
+        const IR::U128 shuffled_x = ir.VectorShuffleWords(x, 0b10010011);
+        const IR::U128 shuffled_y = ir.VectorShuffleWords(y, 0b10010011);
+
+        x = ir.VectorSetElement(32, shuffled_x, 0, new_low_x);
+        y = ir.VectorSetElement(32, shuffled_y, 0, new_low_y);
+    }
+
+    if (part == SHA256HashPart::Part1) {
+        return x;
+    }
+
+    return y;
+}
 } // Anonymous namespace
 
 bool TranslatorVisitor::SHA1C(Vec Vm, Vec Vn, Vec Vd) {
@@ -186,4 +247,16 @@ bool TranslatorVisitor::SHA256SU1(Vec Vm, Vec Vn, Vec Vd) {
     return true;
 }
 
+bool TranslatorVisitor::SHA256H(Vec Vm, Vec Vn, Vec Vd) {
+    const IR::U128 result = SHA256hash(ir, ir.GetQ(Vd), ir.GetQ(Vn), ir.GetQ(Vm), SHA256HashPart::Part1);
+    ir.SetQ(Vd, result);
+    return true;
+}
+
+bool TranslatorVisitor::SHA256H2(Vec Vm, Vec Vn, Vec Vd) {
+    const IR::U128 result = SHA256hash(ir, ir.GetQ(Vn), ir.GetQ(Vd), ir.GetQ(Vm), SHA256HashPart::Part2);
+    ir.SetQ(Vd, result);
+    return true;
+}
+
 } // namespace Dynarmic::A64