From cecc302373f3f0211f5d120fffa513f7189d60f2 Mon Sep 17 00:00:00 2001
From: angie <angheloalf95@gmail.com>
Date: Thu, 6 Feb 2025 16:26:37 -0300
Subject: [PATCH] R5900: Fix decoding the `imm5` operand of the `viaddi`
 instruction as a signed value instead of decoding it as an unsigned one.

---
 CHANGELOG.md                                                 | 5 +++++
 cplusplus/include/instructions/InstructionR5900.hpp          | 2 +-
 cplusplus/src/instructions/InstructionR5900.cpp              | 4 ++--
 .../RabbitizerInstructionR5900_OperandType.c                 | 2 +-
 tests/c/instruction_checks/r5900_disasm.c                    | 2 ++
 5 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fdeea2d..7ff6a48 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- R5900: Fix decoding the `imm5` operand of the `viaddi` instruction as a signed
+  value instead of decoding it as an unsigned one.
+
 ## [1.12.5] - 2024-12-16
 
 ### Fixed
diff --git a/cplusplus/include/instructions/InstructionR5900.hpp b/cplusplus/include/instructions/InstructionR5900.hpp
index d481901..9030083 100644
--- a/cplusplus/include/instructions/InstructionR5900.hpp
+++ b/cplusplus/include/instructions/InstructionR5900.hpp
@@ -33,7 +33,7 @@ namespace rabbitizer {
         uint8_t GetR5900_l() const;
         uint8_t GetR5900_m() const;
 
-        uint8_t GetR5900_imm5() const;
+        int8_t GetR5900_imm5() const;
     };
 };
 
diff --git a/cplusplus/src/instructions/InstructionR5900.cpp b/cplusplus/src/instructions/InstructionR5900.cpp
index 0ef07c1..5a72994 100644
--- a/cplusplus/src/instructions/InstructionR5900.cpp
+++ b/cplusplus/src/instructions/InstructionR5900.cpp
@@ -113,6 +113,6 @@ uint8_t InstructionR5900::GetR5900_m() const {
     return RAB_INSTR_R5900_GET_m(&this->instr);
 }
 
-uint8_t InstructionR5900::GetR5900_imm5() const {
-    return RAB_INSTR_R5900_GET_imm5(&this->instr);
+int8_t InstructionR5900::GetR5900_imm5() const {
+    return RabbitizerUtils_From2Complement(RAB_INSTR_R5900_GET_imm5(&this->instr), 5);
 }
diff --git a/src/instructions/RabbitizerInstructionR5900/RabbitizerInstructionR5900_OperandType.c b/src/instructions/RabbitizerInstructionR5900/RabbitizerInstructionR5900_OperandType.c
index 36398a3..e9bf5f7 100644
--- a/src/instructions/RabbitizerInstructionR5900/RabbitizerInstructionR5900_OperandType.c
+++ b/src/instructions/RabbitizerInstructionR5900/RabbitizerInstructionR5900_OperandType.c
@@ -515,7 +515,7 @@ size_t RabbitizerOperandType_process_r5900_immediate5(const RabbitizerInstructio
         return immOverrideLength;
     }
 
-    number = RAB_INSTR_R5900_GET_imm5(self);
+    number = RabbitizerUtils_From2Complement(RAB_INSTR_R5900_GET_imm5(self), 5);
     if (RabbitizerConfig_Cfg.misc.omit0XOnSmallImm) {
         if (number > -10 && number < 10) {
             RABUTILS_BUFFER_SPRINTF(dst, totalSize, "%i", number);
diff --git a/tests/c/instruction_checks/r5900_disasm.c b/tests/c/instruction_checks/r5900_disasm.c
index fa8c033..336ec13 100644
--- a/tests/c/instruction_checks/r5900_disasm.c
+++ b/tests/c/instruction_checks/r5900_disasm.c
@@ -40,6 +40,8 @@ const TestEntry test_entries[] = {
     TEST_ENTRY_C(0x4A820BFF, NULL, "viswr.y     $vi2, ($vi1)"),
     TEST_ENTRY_C(0x4A420BFF, NULL, "viswr.z     $vi2, ($vi1)"),
     TEST_ENTRY_C(0x4A220BFF, NULL, "viswr.w     $vi2, ($vi1)"),
+
+    TEST_ENTRY_C(0x4A0307B2, NULL, "viaddi      $vi3, $vi0, -0x2"),
 };
 
 size_t test_entries_len = ARRAY_COUNT(test_entries);