/* -------------------------------------------

  Copyright (C) 2024-2025 Amlal EL Mahrous, all rights reserved

------------------------------------------- */

#pragma once

#include <LibCompiler/Defines.h>

// @brief 32x0 support.
// @file Backend/32x0.h

#define kAsmOpcodeDecl(__NAME, __OPCODE, __FUNCT3, __FUNCT7) \
  {.fName = __NAME, .fOpcode = __OPCODE, .fFunct3 = __FUNCT3, .fFunct7 = __FUNCT7},

#define kAsmImmediate 0x01
#define kAsmSyscall 0x02
#define kAsmJump 0x03
#define kAsmNoArgs 0x04

#define kAsmByte 0
#define kAsmHWord 1
#define kAsmWord 2

struct CpuCode32x0 {
  const char fName[32];
  uint8_t    fOpcode;
  uint8_t    fSize;
  uint8_t    fFunct3;
  uint8_t    fFunct7;
};

#define kAsmDWordStr ".dword" /* 64 bit */
#define kAsmWordStr ".word"   /* 32-bit */
#define kAsmHWordStr ".half"  /* 16-bit */
#define kAsmByteStr ".byte"   /* 8-bit */

inline std::vector<CpuCode32x0> kOpcodes32x0 = {
    kAsmOpcodeDecl("nop", 0b0100011, 0b000, kAsmNoArgs)     // nothing to do. (1C)
    kAsmOpcodeDecl("jmp", 0b1110011, 0b001, kAsmJump)       // jump to branch (2C)
    kAsmOpcodeDecl("mov", 0b0100011, 0b101, kAsmImmediate)  // move registers (3C)
    kAsmOpcodeDecl("psh", 0b0111011, 0b000, kAsmImmediate)  // push to sp (2C)
    kAsmOpcodeDecl("pop", 0b0111011, 0b001, kAsmImmediate)  // pop from sp. (1C)
    kAsmOpcodeDecl("lea", 0b0111011, 0b010,
                   kAsmImmediate)  // setup stack and call, store address to CR (1C).
    kAsmOpcodeDecl("ret", 0b0111011, 0b110,
                   kAsmImmediate)                         // return from procedure (2C).
    kAsmOpcodeDecl("uc", 0b0111111, 0b000, kAsmSyscall)   // user call (1C)
    kAsmOpcodeDecl("kc", 0b0111111, 0b001, kAsmSyscall)   // kernel call (1C)
    kAsmOpcodeDecl("int", 0b0111111, 0b010, kAsmSyscall)  // raise interrupt (1C)
};

// \brief 64x0 register prefix
// example: r32, r0
// r32 -> sp
// r0 -> hw zero

#define kAsmRegisterPrefix "r"
#define kAsmRegisterLimit 16
#define kAsmPcRegister 17
#define kAsmCrRegister 18
#define kAsmSpRegister 5

/* return address register */
#define kAsmRetRegister 19

/////////////////////////////////////////////////////////////////////////////

// SYSTEM CALL ADDRESSING

// | OPCODE | FUNCT3 | FUNCT7 |              OFF                 |

// IMMEDIATE ADDRESSING

// | OPCODE | FUNCT3 | FUNCT7 | REG      |  OFF     |
// | OPCODE | FUNCT3 | FUNCT7 | REG      |  OFF     |       REG      |
// | OPCODE | FUNCT3 | FUNCT7 | REG      |  REG     |       OFF      |

// REG TO REG ADDRESSING

// | OPCODE | FUNCT3 | FUNCT7 | REG      |  REG2    |

////////////////////////////////

// LOAD/CALL INTERRUPTS

// SET A HANDLER IN ADDRESS: TODO: find one
// DISABLE INTERRUPTS
// PROCESS INTERRUPT
// ENABLE INTERRUPTS

////////////////////////////////