From bc29d79586fac6efeda57296c68be8293c1f8adb Mon Sep 17 00:00:00 2001
From: Toni <antpiasecki@gmail.com>
Date: Sun, 8 Mar 2026 21:56:04 +0100
Subject: [PATCH] dont include funct* in the Ins struct

---
 LICENSE    |   6 +-
 build.sh   |  16 +++-
 riscv64.cc | 225 ++++++++++++++++++++++++++---------------------------
 3 files changed, 128 insertions(+), 119 deletions(-)

diff --git a/LICENSE b/LICENSE
index 2e16d76..1875e2c 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-BSD 2-Clause License
+BSD 3-Clause License
 
 Copyright (c) 2025-2026, Antoni Piasecki
 
@@ -12,6 +12,10 @@ modification, are permitted provided that the following conditions are met:
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.
 
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
diff --git a/build.sh b/build.sh
index e8574ac..4d30916 100755
--- a/build.sh
+++ b/build.sh
@@ -1,15 +1,23 @@
 #!/bin/bash
 
-COMMON="-g -Wall -Wextra -Wpedantic -Wno-unused-variable"
+CFLAGS="-Wall -Wextra -Wpedantic"
+
+if [[ -n "$RELEASE" ]]; then
+    CFLAGS="$CFLAGS -O3 -flto -march=native"
+else
+    CFLAGS="$CFLAGS -g"
+fi
+
+echo "CFLAGS: $CFLAGS"
 
 echo "building mos6502..."
-cc $COMMON -std=c99 -o mos6502 mos6502.c
+cc $CFLAGS -std=c99 -o mos6502 mos6502.c
 
 if command -v pkg-config >/dev/null; then
     RAYLIB_FLAGS=$(pkg-config --cflags --libs raylib 2>/dev/null)
     if [ $? -eq 0 ]; then
         echo "building chip8..."
-        cc $COMMON -std=c99 -o chip8 chip8.c $RAYLIB_FLAGS
+        cc $CFLAGS -std=c99 -o chip8 chip8.c $RAYLIB_FLAGS
     else
         echo "raylib not found - skipping chip8..."
     fi
@@ -17,7 +25,7 @@ if command -v pkg-config >/dev/null; then
     LIBELF_FLAGS=$(pkg-config --cflags --libs libelf 2>/dev/null)
     if [ $? -eq 0 ]; then
         echo "building riscv64..."
-        c++ -std=c++23 $COMMON -o riscv64 riscv64.cc $LIBELF_FLAGS
+        c++ -std=c++23 $CFLAGS -o riscv64 riscv64.cc $LIBELF_FLAGS
     else
         echo "libelf not found - skipping riscv64..."
     fi
diff --git a/riscv64.cc b/riscv64.cc
index 4e82d3b..f815dad 100644
--- a/riscv64.cc
+++ b/riscv64.cc
@@ -106,12 +106,11 @@ enum Op {
 struct Ins {
   Op op;
   u8 rd;
-  u8 funct3;
   u8 rs1;
-  u8 rs2;
-  u8 funct7;
-  u8 shamt;
-  u8 funct6;
+  union {
+    u8 rs2;
+    u8 shamt;
+  };
   i32 imm;
 };
 
@@ -256,7 +255,7 @@ public:
 
     m_regs[2] = MEMORY_SIZE - 1024; // set the stack pointer
 
-    while (m_pc < m_code_section.offset + m_code_section.size) {
+    while (m_pc < MEMORY_SIZE) {
       m_regs[0] = 0; // clear the zero register
 
       Ins i = m_decoded[(m_pc - m_code_section.offset) / 4];
@@ -282,8 +281,7 @@ public:
         m_regs[i.rd] = m_regs[i.rs1] & m_regs[i.rs2];
       }; break;
       case Op::ANDI: {
-        std::println(stderr, "ANDI unimplemented");
-        exit(1);
+        m_regs[i.rd] = m_regs[i.rs1] & i.imm;
       }; break;
       case Op::AUIPC: {
         m_regs[i.rd] = m_pc + ((i64)i.imm << 12);
@@ -641,7 +639,7 @@ private:
 
     switch (opcode) {
     case 0b1100011: {
-      i.funct3 = (raw >> 12) & 0b111;
+      u8 funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.rs2 = (raw >> 20) & 0b11111;
       i32 imm_12 = (raw >> 31) & 0b1;
@@ -652,110 +650,109 @@ private:
           (imm_12 << 12) | (imm_11 << 11) | (imm_10_5 << 5) | (imm_4_1 << 1);
       i.imm = (i.imm << 19) >> 19;
 
-      if (i.funct3 == 0b000) {
+      if (funct3 == 0b000) {
         i.op = Op::BEQ;
-      } else if (i.funct3 == 0b001) {
+      } else if (funct3 == 0b001) {
         i.op = Op::BNE;
-      } else if (i.funct3 == 0b100) {
+      } else if (funct3 == 0b100) {
         i.op = Op::BLT;
-      } else if (i.funct3 == 0b101) {
+      } else if (funct3 == 0b101) {
         i.op = Op::BGE;
-      } else if (i.funct3 == 0b110) {
+      } else if (funct3 == 0b110) {
         i.op = Op::BLTU;
-      } else if (i.funct3 == 0b111) {
+      } else if (funct3 == 0b111) {
         i.op = Op::BGEU;
       } else {
-        std::println(stderr, "B-type: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "B-type: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
     case 0b0010011: {
+      u8 funct3 = (raw >> 12) & 0b111;
+      u8 funct6 = (raw >> 26) & 0b111111;
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.imm = ((i32)raw) >> 20;
       i.shamt = (raw >> 20) & 0b111111;
-      i.funct6 = (raw >> 26) & 0b111111;
 
-      if (i.funct3 == 0b000) {
+      if (funct3 == 0b000) {
         i.op = Op::ADDI;
-      } else if (i.funct3 == 0b001) {
-        if (i.funct6 == 0b000000) {
+      } else if (funct3 == 0b001) {
+        if (funct6 == 0b000000) {
           i.op = Op::SLLI;
         } else {
           std::println(stderr,
                        "I-type 1: funct3=001: unrecognized funct6: {:b}",
-                       i.funct6);
+                       funct6);
           exit(1);
         }
-      } else if (i.funct3 == 0b010) {
+      } else if (funct3 == 0b010) {
         i.op = Op::SLTI;
-      } else if (i.funct3 == 0b011) {
+      } else if (funct3 == 0b011) {
         i.op = Op::SLTIU;
-      } else if (i.funct3 == 0b100) {
+      } else if (funct3 == 0b100) {
         i.op = Op::XORI;
-      } else if (i.funct3 == 0b101) {
+      } else if (funct3 == 0b101) {
         i.shamt = (raw >> 20) & 0b111111;
-        i.funct6 = (raw >> 26) & 0b111111;
+        funct6 = (raw >> 26) & 0b111111;
 
-        if (i.funct6 == 0b000000) {
+        if (funct6 == 0b000000) {
           i.op = Op::SRLI;
-        } else if (i.funct6 == 0b010000) {
+        } else if (funct6 == 0b010000) {
           i.op = Op::SRAI;
         } else {
           std::println(stderr,
                        "I-type 1: funct3=101: unrecognized funct6: {:b}",
-                       i.funct6);
+                       funct6);
           exit(1);
         }
-      } else if (i.funct3 == 0b110) {
+      } else if (funct3 == 0b110) {
         i.op = Op::ORI;
-      } else if (i.funct3 == 0b111) {
+      } else if (funct3 == 0b111) {
         i.op = Op::ANDI;
       } else {
-        std::println(stderr, "I-type 1: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "I-type 1: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
     case 0b0000011: {
+      u8 funct3 = (raw >> 12) & 0b111;
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.imm = ((i32)raw) >> 20;
 
-      if (i.funct3 == 0b000) {
+      if (funct3 == 0b000) {
         i.op = Op::LB;
-      } else if (i.funct3 == 0b001) {
+      } else if (funct3 == 0b001) {
         i.op = Op::LH;
-      } else if (i.funct3 == 0b010) {
+      } else if (funct3 == 0b010) {
         i.op = Op::LW;
-      } else if (i.funct3 == 0b011) {
+      } else if (funct3 == 0b011) {
         i.op = Op::LD;
-      } else if (i.funct3 == 0b100) {
+      } else if (funct3 == 0b100) {
         i.op = Op::LBU;
-      } else if (i.funct3 == 0b101) {
+      } else if (funct3 == 0b101) {
         i.op = Op::LHU;
-      } else if (i.funct3 == 0b110) {
+      } else if (funct3 == 0b110) {
         i.op = Op::LWU;
       } else {
-        std::println(stderr, "I-type 2: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "I-type 2: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
     case 0b1100111: {
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.imm = ((i32)raw) >> 20;
       i.op = Op::JALR;
     }; break;
     case 0b1110011: {
+      u8 funct3 = (raw >> 12) & 0b111;
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.imm = ((i32)raw) >> 20;
 
-      if (i.funct3 == 0b000) {
+      if (funct3 == 0b000) {
         if (i.imm == 0) {
           i.op = Op::ECALL;
         } else {
@@ -764,7 +761,7 @@ private:
           exit(1);
         }
       } else {
-        std::println(stderr, "I-type 4: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "I-type 4: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
@@ -780,104 +777,104 @@ private:
       i.op = Op::JAL;
     }; break;
     case 0b0110011: {
+      u8 funct3 = (raw >> 12) & 0b111;
+      u8 funct7 = (u8)((raw >> 25) & 0b1111111);
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.rs2 = (raw >> 20) & 0b11111;
-      i.funct7 = (u8)((raw >> 25) & 0b1111111);
 
-      if (i.funct3 == 0b000) {
-        if (i.funct7 == 0b0000000) {
+      if (funct3 == 0b000) {
+        if (funct7 == 0b0000000) {
           i.op = Op::ADD;
-        } else if (i.funct7 == 0b0100000) {
+        } else if (funct7 == 0b0100000) {
           i.op = Op::SUB;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::MUL;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b000: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b001) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b001) {
+        if (funct7 == 0b0000000) {
           i.op = Op::SLL;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::MULH;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b001: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b010) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b010) {
+        if (funct7 == 0b0000000) {
           i.op = Op::SLT;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b010: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b011) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b011) {
+        if (funct7 == 0b0000000) {
           i.op = Op::SLTU;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::MULHU;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b011: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b100) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b100) {
+        if (funct7 == 0b0000000) {
           i.op = Op::XOR;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::DIV;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b100: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b101) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b101) {
+        if (funct7 == 0b0000000) {
           i.op = Op::SRL;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::DIVU;
-        } else if (i.funct7 == 0b0100000) {
+        } else if (funct7 == 0b0100000) {
           i.op = Op::SRA;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b101: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b110) {
-        if (i.funct7 == 0b0000001) {
+      } else if (funct3 == 0b110) {
+        if (funct7 == 0b0000001) {
           i.op = Op::REM;
-        } else if (i.funct7 == 0b0000000) {
+        } else if (funct7 == 0b0000000) {
           i.op = Op::OR;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b110: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b111) {
-        if (i.funct7 == 0b000) {
+      } else if (funct3 == 0b111) {
+        if (funct7 == 0b000) {
           i.op = Op::AND;
-        } else if (i.funct7 == 0b001) {
+        } else if (funct7 == 0b001) {
           i.op = Op::REMU;
         } else {
           std::println(stderr,
                        "R-type 1: funct3=0b111: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
       } else {
-        std::println(stderr, "R-type 1: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "R-type 1: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
@@ -885,76 +882,76 @@ private:
       std::println(stderr, "A extension not implemented yet.");
       exit(1);
     case 0b0111011: {
+      u8 funct3 = (raw >> 12) & 0b111;
+      u8 funct7 = (u8)((raw >> 25) & 0b1111111);
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.rs2 = (raw >> 20) & 0b11111;
-      i.funct7 = (u8)((raw >> 25) & 0b1111111);
 
-      if (i.funct3 == 0b000) {
-        if (i.funct7 == 0b0000000) {
+      if (funct3 == 0b000) {
+        if (funct7 == 0b0000000) {
           i.op = Op::ADDW;
-        } else if (i.funct7 == 0b0100000) {
+        } else if (funct7 == 0b0100000) {
           i.op = Op::SUBW;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::MULW;
         } else {
           std::println(stderr,
                        "R-type 3: funct3=000: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b001) {
+      } else if (funct3 == 0b001) {
         i.op = Op::SLLW;
-      } else if (i.funct3 == 0b100) {
+      } else if (funct3 == 0b100) {
         i.op = Op::DIVW;
-      } else if (i.funct3 == 0b101) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b101) {
+        if (funct7 == 0b0000000) {
           i.op = Op::SRLW;
-        } else if (i.funct7 == 0b0100000) {
+        } else if (funct7 == 0b0100000) {
           i.op = Op::SRAW;
-        } else if (i.funct7 == 0b0000001) {
+        } else if (funct7 == 0b0000001) {
           i.op = Op::DIVUW;
         } else {
           std::println(stderr,
                        "R-type 3: funct3=101: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
-      } else if (i.funct3 == 0b110) {
+      } else if (funct3 == 0b110) {
         i.op = Op::REMW;
-      } else if (i.funct3 == 0b111) {
+      } else if (funct3 == 0b111) {
         i.op = Op::REMUW;
       } else {
-        std::println(stderr, "R-type 3: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "R-type 3: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
     case 0b0011011: {
+      u8 funct3 = (raw >> 12) & 0b111;
+      u8 funct7 = (raw >> 25) & 0b1111111;
       i.rd = (raw >> 7) & 0b11111;
-      i.funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.imm = ((i32)raw) >> 20;
       i.shamt = (raw >> 20) & 0b11111;
-      i.funct7 = (raw >> 25) & 0b1111111;
 
-      if (i.funct3 == 0b000) {
+      if (funct3 == 0b000) {
         i.op = Op::ADDIW;
-      } else if (i.funct3 == 0b001) {
+      } else if (funct3 == 0b001) {
         i.op = Op::SLLIW;
-      } else if (i.funct3 == 0b101) {
-        if (i.funct7 == 0b0000000) {
+      } else if (funct3 == 0b101) {
+        if (funct7 == 0b0000000) {
           i.op = Op::SRLIW;
-        } else if (i.funct7 == 0b0100000) {
+        } else if (funct7 == 0b0100000) {
           i.op = Op::SRAIW;
         } else {
           std::println(stderr,
                        "R-type 4: funct3=101: unrecognized funct7: {:b}",
-                       i.funct7);
+                       funct7);
           exit(1);
         }
       } else {
-        std::println(stderr, "R-type 4: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "R-type 4: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;
@@ -967,7 +964,7 @@ private:
       exit(1);
     }; break;
     case 0b0100011: {
-      i.funct3 = (raw >> 12) & 0b111;
+      u8 funct3 = (raw >> 12) & 0b111;
       i.rs1 = (raw >> 15) & 0b11111;
       i.rs2 = (raw >> 20) & 0b11111;
       i32 imm_11_5 = (raw >> 25) & 0b1111111;
@@ -975,16 +972,16 @@ private:
       i.imm = (imm_11_5 << 5) | imm_4_0;
       i.imm = (i.imm << 20) >> 20;
 
-      if (i.funct3 == 0b000) {
+      if (funct3 == 0b000) {
         i.op = Op::SB;
-      } else if (i.funct3 == 0b001) {
+      } else if (funct3 == 0b001) {
         i.op = Op::SH;
-      } else if (i.funct3 == 0b010) {
+      } else if (funct3 == 0b010) {
         i.op = Op::SW;
-      } else if (i.funct3 == 0b011) {
+      } else if (funct3 == 0b011) {
         i.op = Op::SD;
       } else {
-        std::println(stderr, "S-type: unrecognized funct3: {:03b}", i.funct3);
+        std::println(stderr, "S-type: unrecognized funct3: {:03b}", funct3);
         exit(1);
       }
     }; break;