fix some instruction decodings

decompiler/Disasm/Instruction.cpp

@@ -6,6 +6,7 @@
 
 #include "Instruction.h"
 #include "decompiler/ObjectFile/LinkedObjectFile.h"
+#include "third-party/fmt/core.h"
 #include <cassert>
 
 namespace decompiler {
@@ -26,6 +27,9 @@ std::string InstructionAtom::to_string(const std::vector<DecompilerLabel>& label
       return "Q";
     case IMM_SYM:
       return sym;
+    case VF_FIELD:
+      assert(imm >= 0 && imm < 4);
+      return fmt::format(".{}", "xyzw"[imm]);
     default:
       throw std::runtime_error("Unsupported InstructionAtom");
   }
@@ -77,6 +81,15 @@ void InstructionAtom::set_sym(std::string _sym) {
   sym = std::move(_sym);
 }
 
+/*!
+ * Make this atom a field (x,y,z,w) of a vf.
+ */
+void InstructionAtom::set_vf_field(uint32_t value) {
+  kind = VF_FIELD;
+  imm = value;
+  assert(value < 4);
+}
+
 /*!
  * Get as register, or error if not a register.
  */
@@ -224,7 +237,14 @@ std::string Instruction::to_string(const std::vector<DecompilerLabel>& labels) c
     }
 
     for (uint8_t i = 0; i < n_src; i++) {
-      result += " " + src[i].to_string(labels) + ",";
+      if (src[i].kind == InstructionAtom::VF_FIELD) {
+        if (end_comma) {
+          result.pop_back();
+        }
+        result += src[i].to_string(labels) + ",";
+      } else {
+        result += " " + src[i].to_string(labels) + ",";
+      }
       end_comma = true;
     }
 

decompiler/Disasm/Instruction.h

@@ -16,7 +16,7 @@
 namespace decompiler {
 struct DecompilerLabel;
 
-constexpr int MAX_INSTRUCTION_SOURCE = 3;
+constexpr int MAX_INSTRUCTION_SOURCE = 4;
 constexpr int MAX_INTRUCTION_DEST = 1;
 
 // An "atom", representing a single register, immediate, etc... for use in an Instruction.
@@ -28,6 +28,7 @@ struct InstructionAtom {
     LABEL,     // A label in a LinkedObjectFile
     VU_ACC,    // The VU0 Accumulator
     VU_Q,      // The VU0 Q Register
+    VF_FIELD,  // Field specifier
     INVALID
   } kind = INVALID;
 
@@ -37,6 +38,7 @@ struct InstructionAtom {
   void set_vu_q();
   void set_vu_acc();
   void set_sym(std::string _sym);
+  void set_vf_field(uint32_t value);
 
   Register get_reg() const;
   int32_t get_imm() const;

decompiler/Disasm/InstructionDecode.cpp

@@ -40,11 +40,8 @@ struct OpcodeFields {
   ////////////////
 
   int32_t simm16() { return (int16_t)(data); }
-
   int32_t zimm16() { return (uint16_t)(data); }
-
   uint32_t imm5() { return (data >> 6) & 0x1f; }
-
   uint32_t imm15() { return (data >> 6) & 0b111111111111111; }
 
   ////////////////////
@@ -52,11 +49,8 @@ struct OpcodeFields {
   ////////////////////
 
   uint32_t cop_func() { return (data >> 21) & 0x1f; }
-
   uint32_t ft() { return (data >> 16) & 0x1f; }
-
   uint32_t fs() { return (data >> 11) & 0x1f; }
-
   uint32_t fd() { return (data >> 6) & 0x1f; }
 
   ////////////
@@ -64,16 +58,13 @@ struct OpcodeFields {
   ////////////
 
   uint32_t pcreg() { return (data >> 1) & 0x1f; }
-
   uint32_t syscall() { return (data >> 6) & 0xfffff; }
-
   uint32_t MMI_func() { return (data >> 6) & 0x1f; }
-
   uint32_t lower11() { return (uint32_t)(data & 0x7ff); }
-
   uint32_t lower6() { return (uint32_t)(data & 0b111111); }
-
   uint32_t dest() { return (data >> 21) & 0b1111; }
+  uint32_t fs_f() { return (data >> 21) & 0b11; }
+  uint32_t ft_f() { return (data >> 23) & 0b11; }
 
   uint32_t data;
 };
@@ -1072,6 +1063,12 @@ Instruction decode_instruction(LinkedWord& word, LinkedObjectFile& file, int seg
       case FieldType::ZERO:
         value = 0;
         break;
+      case FieldType::FT_F:
+        value = fields.ft_f();
+        break;
+      case FieldType::FS_F:
+        value = fields.fs_f();
+        break;
       default:
         assert(false);
     }
@@ -1112,6 +1109,9 @@ Instruction decode_instruction(LinkedWord& word, LinkedObjectFile& file, int seg
       case DecodeType::BRANCH_TARGET:
         atom.set_label(file.get_label_id_for(seg_id, (word_id + value + 1) * 4));
         break;
+      case DecodeType::VF_F:
+        atom.set_vf_field(value);
+        break;
 
         // NOTE - these change a property of the instruction and don't add an atom.
       case DecodeType::IL:

decompiler/Disasm/OpcodeInfo.cpp

@@ -405,13 +405,15 @@ void init_opcode_info() {
   def(IK::VDIV, "vdiv")
       .dst(FT::ZERO, DT::VU_Q)
       .src_vf(FT::FS)
+      .src(FT::FS_F, DT::VF_F)
       .src_vf(FT::FT)
-      .src(FT::BC, DT::BC);  // todo
+      .src(FT::FT_F, DT::VF_F);
   def(IK::VRSQRT, "vrsqrt")
       .dst(FT::ZERO, DT::VU_Q)
       .src_vf(FT::FS)
+      .src(FT::FS_F, DT::VF_F)
       .src_vf(FT::FT)
-      .src(FT::BC, DT::BC);  // todo
+      .src(FT::FT_F, DT::VF_F);
   def(IK::VCLIP, "vclip").src(FT::DEST, DT::DEST).src_vf(FT::FS).src_vf(FT::FT);
   def(IK::VMULAQ, "vmulaq")
       .src(FT::DEST, DT::DEST)
@@ -430,7 +432,7 @@ void init_opcode_info() {
 
   def(IK::QMFC2, "qmfc2").src(FT::IL, DT::IL).dst_gpr(FT::RT).src_vf(FT::FS);
   def(IK::QMTC2, "qmtc2").src(FT::IL, DT::IL).src_gpr(FT::RT).dst_vf(FT::FS);
-  def(IK::VSQRT, "vsqrt").src(FT::BC, DT::BC).dst(FT::ZERO, DT::VU_Q).src_vf(FT::FT);
+  def(IK::VSQRT, "vsqrt").dst(FT::ZERO, DT::VU_Q).src_vf(FT::FT).src(FT::FT_F, DT::VF_F);
   def(IK::VRXOR, "vrxor").src(FT::BC, DT::BC).src_vf(FT::FS);
   def(IK::VRNEXT, "vrnext").src(FT::DEST, DT::DEST).dst_vf(FT::FT);
   def(IK::CTC2, "ctc2").src(FT::IL, DT::IL).src_gpr(FT::RT).dst(FT::RD, DT::VI);

decompiler/Disasm/OpcodeInfo.h

@@ -289,6 +289,8 @@ enum class FieldType {
   IMM5,
   IMM15,
   IL,
+  FS_F,
+  FT_F,
   ZERO
 };
 
@@ -305,6 +307,7 @@ enum class DecodeType {
   VCALLMS_TARGET,
   DEST,
   BC,
+  VF_F,
   VU_Q,
   VU_ACC,
   IL

test/CMakeLists.txt

@@ -22,6 +22,7 @@ add_executable(goalc-test
         ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_FormBeforeExpressions.cpp
         ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_FormExpressionBuild.cpp
         ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_FormExpressionBuildLong.cpp
+        ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_InstructionDecode.cpp
         ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_InstructionParser.cpp
         ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_gkernel_decomp.cpp
         ${CMAKE_CURRENT_LIST_DIR}/decompiler/test_math_decomp.cpp

test/decompiler/test_InstructionDecode.cpp

@@ -0,0 +1,36 @@
+#include "gtest/gtest.h"
+#include "decompiler/Disasm/InstructionDecode.h"
+#include "decompiler/Disasm/OpcodeInfo.h"
+#include "decompiler/ObjectFile/LinkedObjectFile.h"
+
+using namespace decompiler;
+
+TEST(InstructionDecode, VDIV) {
+  init_opcode_info();
+  LinkedObjectFile file;
+  u32 vdiv_test = 0b010010'1'10'01'10100'01010'01110111100;
+  //                 ......   z  y  20    10
+  LinkedWord vdiv_word(vdiv_test);
+  auto instr = decode_instruction(vdiv_word, file, 0, 0);
+  EXPECT_EQ(instr.to_string({}), "vdiv Q, vf10.y, vf20.z");
+}
+
+TEST(InstructionDecode, VRSQRT) {
+  init_opcode_info();
+  LinkedObjectFile file;
+  u32 vdiv_test = 0b010010'1'10'01'10100'01010'01110111110;
+  //                 ......   z  y  20    10
+  LinkedWord vdiv_word(vdiv_test);
+  auto instr = decode_instruction(vdiv_word, file, 0, 0);
+  EXPECT_EQ(instr.to_string({}), "vrsqrt Q, vf10.y, vf20.z");
+}
+
+TEST(InstructionDecode, VSQRT) {
+  init_opcode_info();
+  LinkedObjectFile file;
+  u32 vdiv_test = 0b010010'1'10'00'10100'00000'01110111101;
+  //                 ......   z  X  20    X
+  LinkedWord vdiv_word(vdiv_test);
+  auto instr = decode_instruction(vdiv_word, file, 0, 0);
+  EXPECT_EQ(instr.to_string({}), "vsqrt Q, vf20.z");
+}