From fe5abdb3e1746ffed3c844a087247293b4c4190c Mon Sep 17 00:00:00 2001
From: Wunkolo <Wunkolo@gmail.com>
Date: Fri, 28 May 2021 14:24:10 -0700
Subject: [PATCH] backend/x64: Add vfixup constants

Adds compile-time `FixupLUT` function for generating the 32-bit
LUT of src->dst mappings
---
 src/dynarmic/backend/x64/constants.h | 43 ++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/src/dynarmic/backend/x64/constants.h b/src/dynarmic/backend/x64/constants.h
index a458d102..06e947f8 100644
--- a/src/dynarmic/backend/x64/constants.h
+++ b/src/dynarmic/backend/x64/constants.h
@@ -5,6 +5,7 @@
 
 #pragma once
 
+#include "dynarmic/common/bit_util.h"
 #include "dynarmic/common/common_types.h"
 
 namespace Dynarmic::Backend::X64 {
@@ -42,4 +43,46 @@ constexpr u8 b = 0b11001100;
 constexpr u8 c = 0b10101010;
 }  // namespace Tern
 
+// Opcodes for use with vfixupimm
+enum class FpFixup : u8 {
+    A = 0b0000,         // A
+    B = 0b0001,         // B
+    QNaN_B = 0b0010,    // QNaN with sign of B
+    IndefNaN = 0b0011,  // Indefinite QNaN (Negative QNaN with no payload on x86)
+    NegInf = 0b0100,    // -Infinity
+    PosInf = 0b0101,    // +Infinity
+    Inf_B = 0b0110,     // Infinity with sign of B
+    NegZero = 0b0111,   // -0.0
+    PosZero = 0b1000,   // +0.0
+    NegOne = 0b1001,    // -1.0
+    PosOne = 0b1010,    // +1.0
+    Half = 0b1011,      // 0.5
+    Ninety = 0b1100,    // 90.0
+    HalfPi = 0b1101,    // PI/2
+    PosMax = 0b1110,    // +{FLT_MAX,DBL_MAX}
+    NegMax = 0b1111,    // -{FLT_MAX,DBL_MAX}
+};
+
+// Generates 32-bit LUT for vfixupimm instruction
+constexpr u32 FixupLUT(
+    FpFixup src_qnan = FpFixup::A,
+    FpFixup src_snan = FpFixup::A,
+    FpFixup src_zero = FpFixup::A,
+    FpFixup src_posone = FpFixup::A,
+    FpFixup src_neginf = FpFixup::A,
+    FpFixup src_posinf = FpFixup::A,
+    FpFixup src_pos = FpFixup::A,
+    FpFixup src_neg = FpFixup::A) {
+    u32 fixup_lut = 0;
+    fixup_lut = Common::ModifyBits<0, 3, u32>(fixup_lut, static_cast<u32>(src_qnan));
+    fixup_lut = Common::ModifyBits<4, 7, u32>(fixup_lut, static_cast<u32>(src_snan));
+    fixup_lut = Common::ModifyBits<8, 11, u32>(fixup_lut, static_cast<u32>(src_zero));
+    fixup_lut = Common::ModifyBits<12, 15, u32>(fixup_lut, static_cast<u32>(src_posone));
+    fixup_lut = Common::ModifyBits<16, 19, u32>(fixup_lut, static_cast<u32>(src_neginf));
+    fixup_lut = Common::ModifyBits<20, 23, u32>(fixup_lut, static_cast<u32>(src_posinf));
+    fixup_lut = Common::ModifyBits<24, 27, u32>(fixup_lut, static_cast<u32>(src_pos));
+    fixup_lut = Common::ModifyBits<28, 31, u32>(fixup_lut, static_cast<u32>(src_neg));
+    return fixup_lut;
+}
+
 }  // namespace Dynarmic::Backend::X64