feat: compiler_kit: improvements on the assembler and linker.

Signed-off-by: Amlal El Mahrouss <amlal@nekernel.org>

9 files changed, 582 insertions, 113 deletions

diff --git a/doc/specs/NECTAR_LANG.md b/doc/specs/NECTAR_LANG.md
index a175f19..d1f168a 100644
--- a/doc/specs/NECTAR_LANG.md
+++ b/doc/specs/NECTAR_LANG.md
@@ -25,8 +25,16 @@
 - `struct` Data implementation of `impl` -- useful to store fields and such.
 - `let` Pointer/Reference variable declaration.
 - `const` and `let` declaration.
-- Functions.
-- Nested Stubs.
+- Functions support.
+- Nested Stubs support.
+
+===================================
+
+# 2: Operators
+
+===================================
+
+- `:=` Equals/Assign To operator.
 
 ===================================
 
diff --git a/example/example_02_nectar/example.ncpp b/example/example_02_nectar/example.ncpp
index 3f40941..d7ec86c 100644
--- a/example/example_02_nectar/example.ncpp
+++ b/example/example_02_nectar/example.ncpp
@@ -1,6 +1,6 @@
 const main() {
-  if (67 == 67) {
-    return 123;
+  if (0x10 == 0x10) {
+    return 0x137;
   }
 
   return 0;
diff --git a/include/CompilerKit/Detail/AMD64.h b/include/CompilerKit/Detail/AMD64.h
index f1c0671..449ebd1 100644
--- a/include/CompilerKit/Detail/AMD64.h
+++ b/include/CompilerKit/Detail/AMD64.h
@@ -48,9 +48,9 @@ inline std::vector<CpuOpcodeAMD64> kOpcodesAMD64 = {
         CK_ASM_OPCODE("int3", 0xC3) CK_ASM_OPCODE("iret", 0xCF) CK_ASM_OPCODE("retf", 0xCB)
             CK_ASM_OPCODE("retn", 0xC3) CK_ASM_OPCODE("ret", 0xC3) CK_ASM_OPCODE("sti", 0xfb)
                 CK_ASM_OPCODE("cli", 0xfa) CK_ASM_OPCODE("hlt", 0xf4) CK_ASM_OPCODE("nop", 0x90)
-                    CK_ASM_OPCODE("mov", 0x48) CK_ASM_OPCODE("call", 0xFF)
-                        CK_ASM_OPCODE("syscall", 0x0F) CK_ASM_OPCODE("xor", 0x48) CK_ASM_OPCODE(
-                            "push", kAsmPushOpcode) CK_ASM_OPCODE("pop", kAsmPopOpcode)};
+                    CK_ASM_OPCODE("mov", 0x48) CK_ASM_OPCODE("call", 0xFF) CK_ASM_OPCODE(
+                        "syscall", 0x0F) CK_ASM_OPCODE("xor", 0x48) CK_ASM_OPCODE("cmp", 0x39)
+                        CK_ASM_OPCODE("push", kAsmPushOpcode) CK_ASM_OPCODE("pop", kAsmPopOpcode)};
 
 #define kAsmRegisterLimit 16
 
diff --git a/include/CompilerKit/Detail/PreConfig.h b/include/CompilerKit/Detail/PreConfig.h
index c581c76..093917d 100644
--- a/include/CompilerKit/Detail/PreConfig.h
+++ b/include/CompilerKit/Detail/PreConfig.h
@@ -48,8 +48,8 @@
 #include <time.h>
 #include <unistd.h>
 #include <cassert>
-#include <string>
 #include <fstream>
+#include <string>
 
 #define ToString(X) Stringify(X)
 #define Stringify(X) #X
diff --git a/src/CompilerKit/src/Assemblers/Assembler+AMD64.cc b/src/CompilerKit/src/Assemblers/Assembler+AMD64.cc
index a4c8d1f..d90791c 100644
--- a/src/CompilerKit/src/Assemblers/Assembler+AMD64.cc
+++ b/src/CompilerKit/src/Assemblers/Assembler+AMD64.cc
@@ -569,17 +569,16 @@ bool CompilerKit::EncoderAMD64::WriteNumber(const std::size_t& pos, std::string&
 
   switch (jump_label[pos + 1]) {
     case 'x': {
-      if (auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 16); !res) {
-        if (errno != 0) {
-          CompilerKit::Detail::print_error("Invalid hex number: " + jump_label, "CompilerKit");
-          throw std::runtime_error("invalid_hex");
-        }
+      auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 16);
+      res += kOrigin;
+
+      if (errno != 0) {
+        return false;
       }
 
-      CompilerKit::NumberCast64 num =
-          CompilerKit::NumberCast64(strtol(jump_label.substr(pos + 2).c_str(), nullptr, 16));
+      CompilerKit::NumberCast64 num = CompilerKit::NumberCast64(res);
 
-      for (auto& i : num.number) {
+      for (char& i : num.number) {
         if (i == 0) continue;
 
         kAppBytes.push_back(i);
@@ -593,15 +592,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber(const std::size_t& pos, std::string&
       return true;
     }
     case 'b': {
-      if (auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 2); !res) {
-        if (errno != 0) {
-          CompilerKit::Detail::print_error("Invalid binary number: " + jump_label, "CompilerKit");
-          throw std::runtime_error("invalid_bin");
-        }
+      auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 2);
+      res += kOrigin;
+
+      if (errno != 0) {
+        return false;
       }
 
-      CompilerKit::NumberCast64 num =
-          CompilerKit::NumberCast64(strtol(jump_label.substr(pos + 2).c_str(), nullptr, 2));
+      CompilerKit::NumberCast64 num = CompilerKit::NumberCast64(res);
 
       if (kVerbose) {
         kStdOut << "AssemblerAMD64: Found a base 2 number here: " << jump_label.substr(pos) << "\n";
@@ -616,15 +614,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber(const std::size_t& pos, std::string&
       return true;
     }
     case 'o': {
-      if (auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 7); !res) {
-        if (errno != 0) {
-          CompilerKit::Detail::print_error("Invalid octal number: " + jump_label, "CompilerKit");
-          throw std::runtime_error("invalid_octal");
-        }
+      auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 7);
+      res += kOrigin;
+
+      if (errno != 0) {
+        return false;
       }
 
-      CompilerKit::NumberCast64 num =
-          CompilerKit::NumberCast64(strtol(jump_label.substr(pos + 2).c_str(), nullptr, 7));
+      CompilerKit::NumberCast64 num = CompilerKit::NumberCast64(res);
 
       if (kVerbose) {
         kStdOut << "AssemblerAMD64: Found a base 8 number here: " << jump_label.substr(pos) << "\n";
@@ -643,15 +640,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber(const std::size_t& pos, std::string&
     }
   }
 
-  /* check for errno and stuff like that */
-  if (auto res = strtol(jump_label.substr(pos).c_str(), nullptr, 10); !res) {
-    if (errno != 0) {
-      return false;
-    }
+  auto res = strtol(jump_label.substr(pos).c_str(), nullptr, 10);
+  res += kOrigin;
+
+  if (errno != 0) {
+    return false;
   }
 
-  CompilerKit::NumberCast64 num =
-      CompilerKit::NumberCast64(strtol(jump_label.substr(pos).c_str(), nullptr, 10));
+  CompilerKit::NumberCast64 num = CompilerKit::NumberCast64(res);
 
   for (char& i : num.number) {
     if (i == 0) continue;
@@ -871,15 +867,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber8(const std::size_t& pos, std::string
 
   switch (jump_label[pos + 1]) {
     case 'x': {
-      if (auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 16); !res) {
-        if (errno != 0) {
-          CompilerKit::Detail::print_error("Invalid hex number: " + jump_label, "CompilerKit");
-          throw std::runtime_error("invalid_hex");
-        }
+      auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 16);
+      res += kOrigin;
+
+      if (errno != 0) {
+        return false;
       }
 
-      CompilerKit::NumberCast8 num =
-          CompilerKit::NumberCast8(strtol(jump_label.substr(pos + 2).c_str(), nullptr, 16));
+      CompilerKit::NumberCast8 num = CompilerKit::NumberCast8(res);
 
       kAppBytes.push_back(num.number);
 
@@ -891,15 +886,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber8(const std::size_t& pos, std::string
       return true;
     }
     case 'b': {
-      if (auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 2); !res) {
-        if (errno != 0) {
-          CompilerKit::Detail::print_error("Invalid binary number: " + jump_label, "CompilerKit");
-          throw std::runtime_error("invalid_bin");
-        }
+      auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 2);
+      res += kOrigin;
+
+      if (errno != 0) {
+        return false;
       }
 
-      CompilerKit::NumberCast8 num =
-          CompilerKit::NumberCast8(strtol(jump_label.substr(pos + 2).c_str(), nullptr, 2));
+      CompilerKit::NumberCast8 num = CompilerKit::NumberCast8(res);
 
       if (kVerbose) {
         kStdOut << "AssemblerAMD64: Found a base 2 number here: " << jump_label.substr(pos) << "\n";
@@ -910,15 +904,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber8(const std::size_t& pos, std::string
       return true;
     }
     case 'o': {
-      if (auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 7); !res) {
-        if (errno != 0) {
-          CompilerKit::Detail::print_error("Invalid octal number: " + jump_label, "CompilerKit");
-          throw std::runtime_error("invalid_octal");
-        }
+      auto res = strtol(jump_label.substr(pos + 2).c_str(), nullptr, 7);
+      res += kOrigin;
+
+      if (errno != 0) {
+        return false;
       }
 
-      CompilerKit::NumberCast8 num =
-          CompilerKit::NumberCast8(strtol(jump_label.substr(pos + 2).c_str(), nullptr, 7));
+      CompilerKit::NumberCast8 num = CompilerKit::NumberCast8(res);
 
       if (kVerbose) {
         kStdOut << "AssemblerAMD64: Found a base 8 number here: " << jump_label.substr(pos) << "\n";
@@ -933,15 +926,14 @@ bool CompilerKit::EncoderAMD64::WriteNumber8(const std::size_t& pos, std::string
     }
   }
 
-  /* check for errno and stuff like that */
-  if (auto res = strtol(jump_label.substr(pos).c_str(), nullptr, 10); !res) {
-    if (errno != 0) {
-      return false;
-    }
+  auto res = strtol(jump_label.substr(pos).c_str(), nullptr, 10);
+  res += kOrigin;
+
+  if (errno != 0) {
+    return false;
   }
 
-  CompilerKit::NumberCast8 num =
-      CompilerKit::NumberCast8(strtol(jump_label.substr(pos).c_str(), nullptr, 10));
+  CompilerKit::NumberCast8 num = CompilerKit::NumberCast8(res);
 
   kAppBytes.push_back(num.number);
 
@@ -994,6 +986,194 @@ bool CompilerKit::EncoderAMD64::WriteLine(std::string line, std::string file) {
             throw std::runtime_error("syntax_err");
           }
 
+          /// Handle [reg+n] or [reg-n] memory addressing for any register
+          if (substr.find('[') != std::string::npos) {
+            // Parse the memory operand
+            auto bracketStart = substr.find('[');
+            auto bracketEnd   = substr.find(']');
+
+            if (bracketStart == std::string::npos || bracketEnd == std::string::npos) {
+              CompilerKit::Detail::print_error("Syntax error: malformed memory operand.", file);
+              throw std::runtime_error("syntax_err");
+            }
+
+            std::string memOperand = substr.substr(bracketStart + 1, bracketEnd - bracketStart - 1);
+
+            // Register lookup table
+            struct RegInfo {
+              const char* name;
+              i64_byte_t  code;
+            };
+
+            RegInfo regs64[] = {{"rax", 0}, {"rcx", 1}, {"rdx", 2}, {"rbx", 3},
+                                {"rsp", 4}, {"rbp", 5}, {"rsi", 6}, {"rdi", 7}};
+
+            // Find base register in memory operand
+            i64_byte_t baseReg   = 0;
+            bool       foundBase = false;
+
+            for (auto& reg : regs64) {
+              if (memOperand.find(reg.name) != std::string::npos) {
+                baseReg   = reg.code;
+                foundBase = true;
+                break;
+              }
+            }
+
+            if (!foundBase) {
+              CompilerKit::Detail::print_error("Invalid base register in memory operand.", file);
+              throw std::runtime_error("invalid_base_reg");
+            }
+
+            bool isRbp = (baseReg == 5);
+            bool isRsp = (baseReg == 4);
+
+            // Parse displacement
+            int32_t displacement = 0;
+            bool    hasDisp      = false;
+
+            auto plusPos  = memOperand.find('+');
+            auto minusPos = memOperand.find('-');
+
+            if (plusPos != std::string::npos) {
+              std::string dispStr = memOperand.substr(plusPos + 1);
+              displacement        = static_cast<int32_t>(strtol(dispStr.c_str(), nullptr, 0));
+              hasDisp             = true;
+            } else if (minusPos != std::string::npos) {
+              std::string dispStr = memOperand.substr(minusPos + 1);
+              displacement        = -static_cast<int32_t>(strtol(dispStr.c_str(), nullptr, 0));
+              hasDisp             = true;
+            }
+
+            // Determine if destination is memory or register
+            auto commaPos     = substr.find(',');
+            bool destIsMemory = bracketStart < commaPos;
+
+            // Find register in the other operand
+            std::string otherOperand;
+            if (destIsMemory) {
+              otherOperand = substr.substr(commaPos + 1);
+            } else {
+              otherOperand = substr.substr(0, commaPos);
+            }
+
+            // Remove whitespace
+            while (!otherOperand.empty() && (otherOperand[0] == ' ' || otherOperand[0] == '\t')) {
+              otherOperand.erase(0, 1);
+            }
+
+            // Check for register in other operand
+            i64_byte_t regCode     = 0;
+            bool       foundReg    = false;
+            bool       isImmediate = false;
+            int64_t    immValue    = 0;
+
+            for (auto& reg : regs64) {
+              if (otherOperand.find(reg.name) != std::string::npos) {
+                regCode  = reg.code;
+                foundReg = true;
+                break;
+              }
+            }
+
+            if (!foundReg) {
+              // Check if it's an immediate value
+              std::string immStr = otherOperand;
+              while (!immStr.empty() && (immStr[0] == ' ' || immStr[0] == '\t')) {
+                immStr.erase(0, 1);
+              }
+              if (!immStr.empty() && (isdigit(immStr[0]) || immStr[0] == '-')) {
+                isImmediate = true;
+                immValue    = strtol(immStr.c_str(), nullptr, 0);
+              }
+            }
+
+            // Determine mod field based on displacement size
+            // mod=00: [reg] no displacement (except rbp which requires disp8)
+            // mod=01: [reg+disp8]
+            // mod=10: [reg+disp32]
+            i64_byte_t mod = 0;
+            if (!hasDisp && displacement == 0) {
+              // [rbp] requires disp8 with 0, can't use mod=00 (it means RIP-relative)
+              mod = isRbp ? 0x01 : 0x00;
+            } else if (displacement >= -128 && displacement <= 127) {
+              mod = 0x01;  // 8-bit displacement
+            } else {
+              mod = 0x02;  // 32-bit displacement
+            }
+
+            if (destIsMemory) {
+              if (foundReg) {
+                // mov [reg+n], reg
+                kAppBytes.emplace_back(0x48);  // REX.W
+                kAppBytes.emplace_back(0x89);  // MOV r/m64, r64
+
+                // ModR/M: mod | reg << 3 | r/m
+                i64_byte_t modrm = (mod << 6) | (regCode << 3) | baseReg;
+                kAppBytes.emplace_back(modrm);
+
+                // RSP needs SIB byte
+                if (isRsp) {
+                  kAppBytes.emplace_back(0x24);  // SIB: scale=0, index=4(none), base=4(rsp)
+                }
+              } else if (isImmediate) {
+                // mov qword [reg+n], imm32
+                kAppBytes.emplace_back(0x48);  // REX.W
+                kAppBytes.emplace_back(0xC7);  // MOV r/m64, imm32
+
+                // ModR/M: mod | 0 << 3 | r/m (reg field is 0 for this opcode)
+                i64_byte_t modrm = (mod << 6) | (0 << 3) | baseReg;
+                kAppBytes.emplace_back(modrm);
+
+                // RSP needs SIB byte
+                if (isRsp) {
+                  kAppBytes.emplace_back(0x24);
+                }
+              } else {
+                CompilerKit::Detail::print_error("Invalid source operand for mov to memory.", file);
+                throw std::runtime_error("invalid_operand");
+              }
+            } else {
+              // mov reg, [reg+n]
+              kAppBytes.emplace_back(0x48);  // REX.W
+              kAppBytes.emplace_back(0x8B);  // MOV r64, r/m64
+
+              // ModR/M: mod | reg << 3 | r/m
+              i64_byte_t modrm = (mod << 6) | (regCode << 3) | baseReg;
+              kAppBytes.emplace_back(modrm);
+
+              // RSP needs SIB byte
+              if (isRsp) {
+                kAppBytes.emplace_back(0x24);
+              }
+            }
+
+            // Write displacement
+            if (mod == 0x01) {
+              // 8-bit displacement
+              kAppBytes.emplace_back(static_cast<i64_byte_t>(displacement & 0xFF));
+            } else if (mod == 0x02) {
+              // 32-bit displacement
+              kAppBytes.emplace_back(static_cast<i64_byte_t>(displacement & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((displacement >> 8) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((displacement >> 16) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((displacement >> 24) & 0xFF));
+            } else if (isRbp) {
+              // rbp with mod=00 still needs disp8=0
+              kAppBytes.emplace_back(0x00);
+            }
+
+            // Write immediate if present
+            if (destIsMemory && isImmediate) {
+              kAppBytes.emplace_back(static_cast<i64_byte_t>(immValue & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 8) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 16) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 24) & 0xFF));
+            }
+
+            break;
+          }
+
           bool onlyOneReg = true;
 
           std::vector<RegMapAMD64> currentRegList;
@@ -1144,6 +1324,252 @@ bool CompilerKit::EncoderAMD64::WriteLine(std::string line, std::string file) {
           break;
         }
 
+        /// Compare instruction handler.
+        if (name == "cmp") {
+          std::string substr = line.substr(line.find(name) + name.size());
+
+          if (substr.find(",") == std::string::npos) {
+            CompilerKit::Detail::print_error("Syntax error: missing right operand.", "CompilerKit");
+            throw std::runtime_error("syntax_err");
+          }
+
+          // Register lookup table
+          struct RegInfo {
+            const char* name;
+            i64_byte_t  code;
+          };
+
+          RegInfo regs64[] = {{"rax", 0}, {"rcx", 1}, {"rdx", 2}, {"rbx", 3},
+                              {"rsp", 4}, {"rbp", 5}, {"rsi", 6}, {"rdi", 7}};
+
+          /// Handle [reg+n] memory addressing
+          if (substr.find('[') != std::string::npos) {
+            auto bracketStart = substr.find('[');
+            auto bracketEnd   = substr.find(']');
+
+            if (bracketEnd == std::string::npos) {
+              CompilerKit::Detail::print_error("Syntax error: malformed memory operand.", file);
+              throw std::runtime_error("syntax_err");
+            }
+
+            std::string memOperand = substr.substr(bracketStart + 1, bracketEnd - bracketStart - 1);
+
+            // Find base register
+            i64_byte_t baseReg   = 0;
+            bool       foundBase = false;
+
+            for (auto& reg : regs64) {
+              if (memOperand.find(reg.name) != std::string::npos) {
+                baseReg   = reg.code;
+                foundBase = true;
+                break;
+              }
+            }
+
+            if (!foundBase) {
+              CompilerKit::Detail::print_error("Invalid base register in memory operand.", file);
+              throw std::runtime_error("invalid_base_reg");
+            }
+
+            bool isRbp = (baseReg == 5);
+            bool isRsp = (baseReg == 4);
+
+            // Parse displacement
+            int32_t displacement = 0;
+            bool    hasDisp      = false;
+
+            auto plusPos  = memOperand.find('+');
+            auto minusPos = memOperand.find('-');
+
+            if (plusPos != std::string::npos) {
+              std::string dispStr = memOperand.substr(plusPos + 1);
+              displacement        = static_cast<int32_t>(strtol(dispStr.c_str(), nullptr, 0));
+              hasDisp             = true;
+            } else if (minusPos != std::string::npos) {
+              std::string dispStr = memOperand.substr(minusPos + 1);
+              displacement        = -static_cast<int32_t>(strtol(dispStr.c_str(), nullptr, 0));
+              hasDisp             = true;
+            }
+
+            auto commaPos     = substr.find(',');
+            bool destIsMemory = bracketStart < commaPos;
+
+            std::string otherOperand;
+            if (destIsMemory) {
+              otherOperand = substr.substr(commaPos + 1);
+            } else {
+              otherOperand = substr.substr(0, commaPos);
+            }
+
+            while (!otherOperand.empty() && (otherOperand[0] == ' ' || otherOperand[0] == '\t')) {
+              otherOperand.erase(0, 1);
+            }
+
+            i64_byte_t regCode     = 0;
+            bool       foundReg    = false;
+            bool       isImmediate = false;
+            int64_t    immValue    = 0;
+
+            for (auto& reg : regs64) {
+              if (otherOperand.find(reg.name) != std::string::npos) {
+                regCode  = reg.code;
+                foundReg = true;
+                break;
+              }
+            }
+
+            if (!foundReg) {
+              std::string immStr = otherOperand;
+              while (!immStr.empty() && (immStr[0] == ' ' || immStr[0] == '\t')) {
+                immStr.erase(0, 1);
+              }
+              if (!immStr.empty() && (isdigit(immStr[0]) || immStr[0] == '-')) {
+                isImmediate = true;
+                immValue    = strtol(immStr.c_str(), nullptr, 0);
+              }
+            }
+
+            // Determine mod field
+            i64_byte_t mod = 0;
+            if (!hasDisp && displacement == 0) {
+              mod = isRbp ? 0x01 : 0x00;
+            } else if (displacement >= -128 && displacement <= 127) {
+              mod = 0x01;
+            } else {
+              mod = 0x02;
+            }
+
+            if (destIsMemory) {
+              if (foundReg) {
+                // cmp [reg+n], reg
+                kAppBytes.emplace_back(0x48);  // REX.W
+                kAppBytes.emplace_back(0x39);  // CMP r/m64, r64
+
+                i64_byte_t modrm = (mod << 6) | (regCode << 3) | baseReg;
+                kAppBytes.emplace_back(modrm);
+
+                if (isRsp) {
+                  kAppBytes.emplace_back(0x24);
+                }
+              } else if (isImmediate) {
+                // cmp qword [reg+n], imm32
+                kAppBytes.emplace_back(0x48);  // REX.W
+                kAppBytes.emplace_back(0x81);  // CMP r/m64, imm32
+
+                // reg field = 7 for CMP
+                i64_byte_t modrm = (mod << 6) | (7 << 3) | baseReg;
+                kAppBytes.emplace_back(modrm);
+
+                if (isRsp) {
+                  kAppBytes.emplace_back(0x24);
+                }
+              }
+            } else {
+              // cmp reg, [reg+n]
+              kAppBytes.emplace_back(0x48);  // REX.W
+              kAppBytes.emplace_back(0x3B);  // CMP r64, r/m64
+
+              i64_byte_t modrm = (mod << 6) | (regCode << 3) | baseReg;
+              kAppBytes.emplace_back(modrm);
+
+              if (isRsp) {
+                kAppBytes.emplace_back(0x24);
+              }
+            }
+
+            // Write displacement
+            if (mod == 0x01) {
+              kAppBytes.emplace_back(static_cast<i64_byte_t>(displacement & 0xFF));
+            } else if (mod == 0x02) {
+              kAppBytes.emplace_back(static_cast<i64_byte_t>(displacement & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((displacement >> 8) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((displacement >> 16) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((displacement >> 24) & 0xFF));
+            } else if (isRbp) {
+              kAppBytes.emplace_back(0x00);
+            }
+
+            // Write immediate
+            if (destIsMemory && isImmediate) {
+              kAppBytes.emplace_back(static_cast<i64_byte_t>(immValue & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 8) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 16) & 0xFF));
+              kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 24) & 0xFF));
+            }
+
+            break;
+          }
+
+          // Handle register-to-register and register-to-immediate
+          i64_byte_t reg1Code    = 0;
+          i64_byte_t reg2Code    = 0;
+          bool       foundReg1   = false;
+          bool       foundReg2   = false;
+          bool       isImmediate = false;
+          int64_t    immValue    = 0;
+
+          auto        commaPos     = substr.find(',');
+          std::string leftOperand  = substr.substr(0, commaPos);
+          std::string rightOperand = substr.substr(commaPos + 1);
+
+          while (!leftOperand.empty() && (leftOperand[0] == ' ' || leftOperand[0] == '\t')) {
+            leftOperand.erase(0, 1);
+          }
+          while (!rightOperand.empty() && (rightOperand[0] == ' ' || rightOperand[0] == '\t')) {
+            rightOperand.erase(0, 1);
+          }
+
+          for (auto& reg : regs64) {
+            if (leftOperand.find(reg.name) != std::string::npos) {
+              reg1Code  = reg.code;
+              foundReg1 = true;
+              break;
+            }
+          }
+
+          for (auto& reg : regs64) {
+            if (rightOperand.find(reg.name) != std::string::npos) {
+              reg2Code  = reg.code;
+              foundReg2 = true;
+              break;
+            }
+          }
+
+          if (!foundReg2) {
+            if (!rightOperand.empty() && (isdigit(rightOperand[0]) || rightOperand[0] == '-')) {
+              isImmediate = true;
+              immValue    = strtol(rightOperand.c_str(), nullptr, 0);
+            }
+          }
+
+          if (foundReg1 && foundReg2) {
+            // cmp reg1, reg2
+            kAppBytes.emplace_back(0x48);  // REX.W
+            kAppBytes.emplace_back(0x39);  // CMP r/m64, r64
+
+            i64_byte_t modrm = (0x3 << 6) | (reg2Code << 3) | reg1Code;
+            kAppBytes.emplace_back(modrm);
+          } else if (foundReg1 && isImmediate) {
+            // cmp reg, imm
+            kAppBytes.emplace_back(0x48);  // REX.W
+            kAppBytes.emplace_back(0x81);  // CMP r/m64, imm32
+
+            // reg field = 7 for CMP
+            i64_byte_t modrm = (0x3 << 6) | (7 << 3) | reg1Code;
+            kAppBytes.emplace_back(modrm);
+
+            kAppBytes.emplace_back(static_cast<i64_byte_t>(immValue & 0xFF));
+            kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 8) & 0xFF));
+            kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 16) & 0xFF));
+            kAppBytes.emplace_back(static_cast<i64_byte_t>((immValue >> 24) & 0xFF));
+          } else {
+            CompilerKit::Detail::print_error("Invalid operands for cmp instruction.", file);
+            throw std::runtime_error("invalid_cmp_operands");
+          }
+
+          break;
+        }
+
         /// Push instruction handler.
         if (name == "push" || name == "pop") {
           std::string substr = line.substr(line.find(name) + name.size());
diff --git a/src/CompilerKit/src/Compilers/NectarCompiler+AMD64.cc b/src/CompilerKit/src/Compilers/NectarCompiler+AMD64.cc
index 720fdee..1889035 100644
--- a/src/CompilerKit/src/Compilers/NectarCompiler+AMD64.cc
+++ b/src/CompilerKit/src/Compilers/NectarCompiler+AMD64.cc
@@ -345,33 +345,59 @@ CompilerKit::SyntaxLeafList::SyntaxLeaf CompilerFrontendNectarAMD64::Compile(
           left.erase(left.find(" "), 1);
         }
 
-        auto right = left.substr(left.find_first_of("==") + 2);
-
-        auto tmp = left.substr(0, left.find_first_of("=="));
-        left     = std::move(tmp);
-
-        syntax_tree.fUserValue +=
-            "mov rdi, " +
-            (isnumber(left[0])
-                 ? left
-                 : (nectar_get_variable_ref(left).empty() ? left : nectar_get_variable_ref(left))) +
-            "\n";
-
-        syntax_tree.fUserValue += "mov rsi, " +
-                                  (isnumber(right[0]) ? right
-                                                      : (nectar_get_variable_ref(right).empty()
-                                                             ? right
-                                                             : nectar_get_variable_ref(right))) +
-                                  "\n";
+        std::vector<std::pair<CompilerKit::STLString, CompilerKit::STLString>> operators = {
+            {"==", "je"}, {"!=", "jne"}, {">=", "jge"}, {"<=", "jle"}, {">", "jg"}, {"<", "jl"},
+        };
+
+        for (auto& op : operators) {
+          if (left.find(op.first) == CompilerKit::STLString::npos) continue;
+
+          auto right = left.substr(left.find(op.first) + op.first.size());
+
+          auto tmp = left.substr(0, left.find(op.first));
+          left     = std::move(tmp);
+
+          if (!nectar_get_variable_ref(left).empty())
+            syntax_tree.fUserValue += "mov rdi, " +
+                                      (isnumber(left[0]) ? left
+                                                         : (nectar_get_variable_ref(left).empty()
+                                                                ? left
+                                                                : nectar_get_variable_ref(left))) +
+                                      "\n";
+          else
+            syntax_tree.fUserValue += "mov rdi, " +
+                                      (isnumber(left[0]) ? left
+                                                         : (nectar_get_variable_ref(left).empty()
+                                                                ? left
+                                                                : nectar_get_variable_ref(left))) +
+                                      "\n";
+
+          if (!nectar_get_variable_ref(left).empty())
+            syntax_tree.fUserValue +=
+                "lea rsi, " +
+                (isnumber(right[0])
+                     ? right
+                     : (nectar_get_variable_ref(right).empty() ? right
+                                                               : nectar_get_variable_ref(right))) +
+                "\n";
+          else
+            syntax_tree.fUserValue +=
+                "mov rsi, " +
+                (isnumber(right[0])
+                     ? right
+                     : (nectar_get_variable_ref(right).empty() ? right
+                                                               : nectar_get_variable_ref(right))) +
+                "\n";
 
-        syntax_tree.fUserValue += "cmp rdi, rsi\n";
+          syntax_tree.fUserValue += "cmp rdi, rsi\n";
 
-        syntax_tree.fUserValue +=
-            "jne __ret_" + std::to_string(kOrigin) + "_" + kCurrentFunctionName + "\n";
+          syntax_tree.fUserValue +=
+              op.second + " __ret_" + std::to_string(kOrigin) + "_" + kCurrentFunctionName + "\n";
 
-        kCurrentFunctionName = std::to_string(kOrigin) + "_" + kCurrentFunctionName;
+          kCurrentFunctionName = std::to_string(kOrigin) + "_" + kCurrentFunctionName;
 
-        ++kOrigin;
+          ++kOrigin;
+        }
 
         break;
       }
@@ -776,8 +802,12 @@ CompilerKit::SyntaxLeafList::SyntaxLeaf CompilerFrontendNectarAMD64::Compile(
             kExternalSymbols.insert(mangled + valueOfVar);
 
             if (!kNasmOutput) {
-              syntax_tree.fUserValue += instr + nectar_get_variable_ref(varName) + ", __thiscall " +
-                                        mangled + valueOfVar + "\n";
+              if (valueOfVar.ends_with(")"))
+                syntax_tree.fUserValue += instr + nectar_get_variable_ref(varName) +
+                                          ", __thiscall " + mangled + valueOfVar + "\n";
+              else
+                syntax_tree.fUserValue +=
+                    instr + nectar_get_variable_ref(varName) + ", " + mangled + valueOfVar + "\n";
             } else {
               // NASM: Generate call and move result
               syntax_tree.fUserValue += "call " + mangled + valueOfVar + "\n";
@@ -816,7 +846,7 @@ CompilerKit::SyntaxLeafList::SyntaxLeaf CompilerFrontendNectarAMD64::Compile(
 
           auto ref = nectar_get_variable_ref(subText);
 
-          if (ref.empty() == false) syntax_tree.fUserValue += "mov rax, " + ref + "\n";
+          if (ref.empty() == false) syntax_tree.fUserValue += "lea rax, " + ref + "\n";
 
           if (subText.starts_with("'") || isnumber(subText[0]))
             syntax_tree.fUserValue += "mov rax, " + subText + "\n";
@@ -841,7 +871,8 @@ CompilerKit::SyntaxLeafList::SyntaxLeaf CompilerFrontendNectarAMD64::Compile(
         }
 
         if (!kNasmOutput)
-          syntax_tree.fUserValue += "public_segment .code64 __ret_" + kCurrentFunctionName + "\n";
+          syntax_tree.fUserValue +=
+              "public_segment .code64 __ret_" + kCurrentFunctionName + "\nnop\n";
         else
           syntax_tree.fUserValue += "__ret_" + kCurrentFunctionName + ":\n";
 
@@ -1033,12 +1064,12 @@ static CompilerKit::STLString nectar_mangle_name(const CompilerKit::STLString& i
 
 /// \brief Generate function prologue
 static CompilerKit::STLString nectar_generate_prologue() {
-  return "push rbp\nmov rbp, rsp\n";
+  return "";
 }
 
 /// \brief Generate function epilogue
 static CompilerKit::STLString nectar_generate_epilogue() {
-  return "mov rsp, rbp\npop rbp\n";
+  return "";
 }
 
 /// \brief Allocate a variable on the stack
@@ -1107,7 +1138,7 @@ static CompilerKit::STLString nectar_get_variable_ref(const CompilerKit::STLStri
     return varInfo->fRegister;
   } else {
     // Stack or spilled
-    return "qword [rbp" + std::to_string(varInfo->fStackOffset) + "]";
+    return "qword [rbp+" + std::to_string(-varInfo->fStackOffset) + "]";
   }
 }
 
@@ -1188,10 +1219,10 @@ static CompilerKit::STLString nectar_spill_lru_variable() {
 
   /// if impl init
   if (!lruVar->fRegister.ends_with("{}"))
-    spillCode =
-        "mov qword [rbp" + std::to_string(kContext.fStackOffset) + "], " + lruVar->fRegister + "\n";
+    spillCode = "mov qword [rbp+" + std::to_string(-kContext.fStackOffset) + "], " +
+                lruVar->fRegister + "\n";
   else
-    spillCode = "mov qword [rbp" + std::to_string(kContext.fStackOffset) + "], rax\n";
+    spillCode = "mov qword [rbp+" + std::to_string(-kContext.fStackOffset) + "], rax\n";
 
   // Update variable info
   lruVar->fLocation    = VarLocation::kStackSpill;
@@ -1255,7 +1286,7 @@ static CompilerKit::STLString nectar_generate_constructor_call(
   nectar_pop_scope();
 
   CompilerKit::STLString code;
-  code += "lea r8, [rbp" + std::to_string(offset) + "]\n";
+  code += "lea r8, [rbp+" + std::to_string(offset) + "]\n";
   code += "call " + ctor_mangled + "\n";
   return code;
 }
@@ -1274,7 +1305,7 @@ static CompilerKit::STLString nectar_generate_destructor_call(
 
   CompilerKit::STLString code;
   if (varInfo->fLocation == VarLocation::kStack || varInfo->fLocation == VarLocation::kStackSpill) {
-    code += "lea r8, [rbp" + std::to_string(varInfo->fStackOffset) + "]\n";
+    code += "lea r8, [rbp+" + std::to_string(varInfo->fStackOffset) + "]\n";
   } else {
     code += "mov r8, " + varInfo->fRegister + "\n";
   }
diff --git a/src/CompilerKit/src/Linkers/DynamicLinker64+MachO.cc b/src/CompilerKit/src/Linkers/DynamicLinker64+MachO.cc
index f87e2fc..f076d3c 100644
--- a/src/CompilerKit/src/Linkers/DynamicLinker64+MachO.cc
+++ b/src/CompilerKit/src/Linkers/DynamicLinker64+MachO.cc
@@ -46,17 +46,17 @@ static std::vector<CompilerKit::Detail::Blob> kTextBytes;
 static std::vector<CompilerKit::Detail::Blob> kDataBytes;
 
 /* symbol table */
-static std::vector<nlist_64>                      kSymbolTable;
-static std::vector<Char>                          kStringTable;
+static std::vector<nlist_64>                    kSymbolTable;
+static std::vector<Char>                        kStringTable;
 static std::map<CompilerKit::STLString, UInt64> kSymbolOffsets;
 
 /// @brief Structure to hold section information from AE records
 struct SectionInfo {
   CompilerKit::STLString name;
-  UInt32               kind;
+  UInt32                 kind;
   std::vector<Char>      bytes;
-  UInt64               address;
-  UInt64               size;
+  UInt64                 address;
+  UInt64                 size;
 };
 
 /// @brief Extract clean symbol name from AE record name
@@ -87,7 +87,7 @@ static CompilerKit::STLString ExtractSymbolName(const CompilerKit::STLString& ae
 
 /// @brief Add a symbol to the symbol table
 static UInt32 AddSymbol(const CompilerKit::STLString& name, uint8_t type, uint8_t sect,
-                          UInt64 value) {
+                        UInt64 value) {
   // Add name to string table (offset 0 is reserved for empty string)
   if (kStringTable.empty()) {
     kStringTable.push_back('\0');  // First byte is null
@@ -345,7 +345,7 @@ NECTAR_MODULE(DynamicLinker64MachO) {
   using namespace CompilerKit::MachO;
 
   UInt32 numCommands = 8;  // __PAGEZERO, LC_BUILD_VERSION, __TEXT, __LINKEDIT, LC_LOAD_DYLINKER,
-                             // LC_UUID, LC_SYMTAB, LC_DYSYMTAB
+                           // LC_UUID, LC_SYMTAB, LC_DYSYMTAB
 
   if (!kIsDylib) {
     numCommands += 1;  // LC_MAIN
diff --git a/src/CompilerKit/src/Linkers/DynamicLinker64+PEF.cc b/src/CompilerKit/src/Linkers/DynamicLinker64+PEF.cc
index ea513c5..b0a142e 100644
--- a/src/CompilerKit/src/Linkers/DynamicLinker64+PEF.cc
+++ b/src/CompilerKit/src/Linkers/DynamicLinker64+PEF.cc
@@ -202,8 +202,8 @@ NECTAR_MODULE(DynamicLinker64PEF) {
   pef_container.Count    = 0UL;
   pef_container.Kind     = is_executable ? CompilerKit::kPefKindExec : CompilerKit::kPefKindDylib;
   pef_container.SubCpu   = kSubArch;
-  pef_container.Linker   = kLinkerId;  // Amlal El Mahrouss Linker
-  pef_container.Abi      = static_cast<Int32>(kAbi);       // Multi-Processor UX ABI
+  pef_container.Linker   = kLinkerId;                 // Nectar Linker
+  pef_container.Abi      = static_cast<Int32>(kAbi);  // Multi-Processor UX ABI
   pef_container.Magic[0] = kPefMagic[kFatBinaryEnable ? 2 : 0];
   pef_container.Magic[1] = kPefMagic[1];
   pef_container.Magic[2] = kPefMagic[kFatBinaryEnable ? 0 : 2];
@@ -552,8 +552,8 @@ NECTAR_MODULE(DynamicLinker64PEF) {
   // And check for any duplications
   for (size_t commandHeaderIndex = 0UL; commandHeaderIndex < command_headers.size();
        ++commandHeaderIndex) {
-    if (CompilerKit::STLString(command_headers[commandHeaderIndex].Name).find(kLinkerDefineSymbol) !=
-            CompilerKit::STLString::npos &&
+    if (CompilerKit::STLString(command_headers[commandHeaderIndex].Name)
+                .find(kLinkerDefineSymbol) != CompilerKit::STLString::npos &&
         CompilerKit::STLString(command_headers[commandHeaderIndex].Name).find(kLinkerDynamicSym) ==
             CompilerKit::STLString::npos) {
       // ignore :UndefinedSymbol: headers, they do not contain code.
diff --git a/test/test_samples/test_printf.ncpp b/test/test_samples/test_printf.ncpp
index 60a6dbb..d18c818 100644
--- a/test/test_samples/test_printf.ncpp
+++ b/test/test_samples/test_printf.ncpp
@@ -1,5 +1,9 @@
 let main()
 {
-    let ret := 100;
-    return ret;
+    if (0x01 <= 0x100) 
+    {
+        return 0x80;
+    }
+
+    return 0x0;
 }
\ No newline at end of file