137 lines
4.9 KiB
C
137 lines
4.9 KiB
C
//
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// Created by bruno on 2.2.2025.
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//
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#ifndef RISCB_CORE_H
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#define RISCB_CORE_H
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#include <stdint.h>
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#include "stdio.h"
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#define MEM_SIZE 65535
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// Register count (register names R0 to R7)
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#define REG_COUNT 64
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#define STACK_SIZE 255
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#define CPU_FLAG_ZERO (1 << 0)
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#define CPU_FLAG_NEGATIVE (1 << 1)
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#define CPU_MODE_PAUSED (1 << 0)
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#define CPU_MODE_HALTED (1 << 1)
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#define CPU_MODE_ERROR (1 << 2)
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#define CPU_MODE_LOOP (1 << 3)
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#define CPU_MODE_STEP (1 << 4)
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#define CPU_MODE_SECOND (1 << 5)
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#define CPU_INSTRUCTION_SIZE 8 //Biggest instruction
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// CPU state
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typedef struct {
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uint8_t regs[REG_COUNT];
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uint8_t memory[MEM_SIZE];
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uint32_t stack[STACK_SIZE]; // Stack pointer
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uint32_t addrToLineMapper[MEM_SIZE / CPU_INSTRUCTION_SIZE];
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uint32_t pc; // Program counter
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uint32_t stack_ptr; // Stack pointer
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uint8_t flags; // Status flags
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uint32_t programEnd;
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uint8_t mode;
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uint32_t cycle;
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} CPU;
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void step(CPU *cpu);
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void init_cpu(CPU *cpu);
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// Helper function for setting flags in the CPU (here we assume bit0 is the Zero flag,
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// and bit1 is the Negative flag).
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static inline void set_flags(CPU *cpu, int32_t result);
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// Opcode definitions (should match the CPU’s enum)
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typedef enum {
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NOP, // NOP - No operation (does nothing, advances to next instruction)
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BRK, // BRK - Pause CPU (halts execution until resumed)
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HLT,
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MOV_RN_IMM, // MOV Rn, Imm - Move immediate to register (Rn = Imm)
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MOV_RN_RM, // MOV Rn, Rm - Move value from one register to another (Rn = Rm)
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MOV_RN_ADDR, // MOV Rn, [Addr] - Load value from memory address into register (Rn = [Addr])
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MOV_ADDR_RN, // MOV [Addr], Rn - Store register value into memory address ([Addr] = Rn)
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SWAP, // SWAP Rn, Rm - Swap values between two registers (Rn <-> Rm)
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SWAPN, // SWAPN Rn - Swap nibbles within a register (Rn high/low nibbles swapped)
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ADD_RN_RM, // ADD Rn, Rm - Add values of two registers (Rn = Rn + Rm)
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ADD_RN_IMM, // ADD Rn, Imm - Add immediate value to register (Rn = Rn + Imm)
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SUB_RN_RM, // SUB Rn, Rm - Subtract one register from another (Rn = Rn - Rm)
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SUB_RN_IMM, // SUB Rn, Imm - Subtract immediate value from register (Rn = Rn - Imm)
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MUL_RN_RM, // MUL Rn, Rm - Multiply two registers (Rn = Rn * Rm)
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MUL_RN_IMM, // MUL Rn, Imm - Multiply register by immediate (Rn = Rn * Imm)
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DIV_RN_RM, // DIV Rn, Rm - Divide one register by another (Rn = Rn / Rm)
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DIV_RN_IMM, // DIV Rn, Imm - Divide register by immediate (Rn = Rn / Imm)
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MOD_RN_RM, // MOD Rn, Rm - Compute remainder of division (Rn = Rn % Rm)
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MOD_RN_IMM, // MOD Rn, Imm - Compute remainder using immediate (Rn = Rn % Imm)
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NEG_RN, // NEG Rn - Negate register value (Rn = -Rn)
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AND_RN_RM, // AND Rn, Rm - Bitwise AND two registers (Rn = Rn & Rm)
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AND_RN_IMM, // AND Rn, Imm - Bitwise AND register with immediate (Rn = Rn & Imm)
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OR_RN_RM, // OR Rn, Rm - Bitwise OR two registers (Rn = Rn | Rm)
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OR_RN_IMM, // OR Rn, Imm - Bitwise OR register with immediate (Rn = Rn | Imm)
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XOR_RN_RM, // XOR Rn, Rm - Bitwise XOR two registers (Rn = Rn ^ Rm)
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XOR_RN_IMM, // XOR Rn, Imm - Bitwise XOR register with immediate (Rn = Rn ^ Imm)
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NOT_RN, // NOT Rn - Bitwise NOT (Rn = ~Rn)
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SHL_RN_IMM, // SHL Rn, Imm - Logical shift left (Rn = Rn << Imm)
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SHR_RN_IMM, // SHR Rn, Imm - Logical shift right (Rn = Rn >> Imm)
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SAR_RN_IMM, // SAR Rn, Imm - Arithmetic shift right (Rn = Rn >> Imm with sign extension)
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JMP, // JMP Addr - Jump to address (PC = Addr)
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JMP_REL, // JMP Offset - relative jump (offset is signed)
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INC_RN, //INC Rn - Increment register
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INC_ADDR, //INC [Addr] - Increment address
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DEC_RN, //DEC Rn - Increment register
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DEC_ADDR, //DEC [Addr] - Increment address
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CMP, // CMP Rn, Rm - Compare two registers (sets flags based on Rn - Rm)
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JE, // JE Addr - Jump if equal (if zero flag set, PC = Addr)
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JNE, // JNE Addr - Jump if not equal (if zero flag not set, PC = Addr)
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JMP_BIT_SET_RN, // jump relative if a given bit in a register is set
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JMP_BIT_SET_ADDR, // jump relative if a given bit in memory is set
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JMP_BIT_CLEAR_RN, // jump relative if a given bit in a register is not set
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JMP_BIT_CLEAR_ADDR, // jump relative if a given bit in memory is not set
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JG, // JG Addr - Jump if greater (if greater flag set, PC = Addr)
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JL, // JL Addr - Jump if less (if less flag set, PC = Addr)
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JGE, // JGE Addr - Jump if greater or equal (if greater or zero flag set, PC = Addr)
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JLE, // JLE Addr - Jump if less or equal (if less or zero flag set, PC = Addr)
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CALL, // CALL Addr - Call subroutine (push PC, flags and registers to stack, PC = Addr)
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RET, // RET - Return from subroutine (pop PC, flags and registers from stack)
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} Opcode;
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#endif //RISCB_CORE_H
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