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#pragma once
/*
* Follows the general 8-bit opcodes:
*
* See http://www.c-jump.com/CIS77/CPU/IsaDesign/lecture.html
*
* iiirrmmm (general two operand opcode format)
*
* iii instruction/opcode group
* rr register operand
* mmm second operand
*
* iii = 000 special commands (zero or one operand)
* = 001 or
* = 010 and
* = 011 cmp
* = 100 sub
* = 101 add
* = 11x mov
* = 110 mov (load)
* = 111 mov (store)
*
* rr = 00 AX
* 01 BX
* 10 CX
* 11 DX
*
* mmm = 000 AX
* 001 BX
* 010 CX
* 011 DX
* 100 illegal
* 101 illegal
* 110 direct memory
* 111 constant
*
* 000iimmm (general one operand opcode format)
*
* ii instruction/opcode group
* mmm operand
*
* ii = 00 (special commands) zero-operand commands
* = 01 jump instructions
* = 10 not
* = 11 stack (push and pop registers to/from stack)
*
* for jmp:
*
* mmm = 000 je (Z set)
* 001 jne (Z not set)
* 010 jb (C set)
* 011 jbe (C set or Z set)
* 100 ja (C not set and Z not set)
* 101 jae (C not set)
* 110 jmp (unconditional)
* 111 jsr (subroutine call, push PC on stack)
*
* for not:
*
* mmm = 000 AX
* 001 BX
* 010 CX
* 011 DX
* 100 illegal
* 101 illegal
* 110 illegal
* 111 illegal
*
* for push/pop
*
* mmm = 000 push AX
* 001 push BX
* 010 push CX
* 011 push DX
* 100 pop AX
* 101 pop BX
* 110 pop CX
* 111 pop DX
*
* 00000iii zero-operand instructions
*
* iii instruction/opcode group
*
* iii = 000 illegal
* = 001 nop
* = 010 hlt
* = 011 ret (return from subroute call, restore PC from stack)
* = 100 illegal
* = 101 illegal
* = 110 illegal
* = 111 illegal
*
*/
typedef enum Opcode {
OPCODE_GROUP_ZERO_OPERANDS = (unsigned char)0x07,
OPCODE_GROUP_ONE_OPERAND = (unsigned char)0x18,
OPCODE_GROUP_TWO_OPERANDS = (unsigned char)0xe0,
OPCODE_MOV_MASK = (unsigned char)0xc0,
OPCODE_MOV_LD = (unsigned char)0xc0,
OPCODE_MOV_ST = (unsigned char)0xe8,
OPCODE_DST_MASK = (unsigned char)0x18,
OPCODE_DST_AX_REG = (unsigned char)0x00,
OPCODE_DST_BX_REG = (unsigned char)0x08,
OPCODE_DST_CX_REG = (unsigned char)0x10,
OPCODE_DST_DX_REG = (unsigned char)0x18,
OPCODE_SRC_MASK = (unsigned char)0x07,
OPCODE_SRC_AX_REG = (unsigned char)0x00,
OPCODE_SRC_BX_REG = (unsigned char)0x01,
OPCODE_SRC_CX_REG = (unsigned char)0x02,
OPCODE_SRC_DX_REG = (unsigned char)0x03,
OPCODE_SRC_CONST = (unsigned char)0x07,
OPCODE_SRC_MEMORY = (unsigned char)0x06,
OPCODE_OR = (unsigned char)0x20,
OPCODE_AND = (unsigned char)0x40,
OPCODE_CMP = (unsigned char)0x60,
OPCODE_SUB = (unsigned char)0x80,
OPCODE_ADD = (unsigned char)0xa0,
OPCODE_JMP = (unsigned char)0x08,
OPCODE_JMP_MASK = (unsigned char)0x07,
OPCODE_JMP_JE = (unsigned char)0x00,
OPCODE_JMP_JNE = (unsigned char)0x01,
OPCODE_JMP_JB = (unsigned char)0x02,
OPCODE_JMP_JBE = (unsigned char)0x03,
OPCODE_JMP_JA = (unsigned char)0x04,
OPCODE_JMP_JAE = (unsigned char)0x05,
OPCODE_JMP_JMP = (unsigned char)0x06,
OPCODE_JMP_JSR = (unsigned char)0x07,
OPCODE_NOT = (unsigned char)0x10,
OPCODE_STACK = (unsigned char)0x18,
OPCODE_STACK_OPERAND_MASK = (unsigned char)0x3,
OPCODE_STACK_PUSH = (unsigned char)0x0,
OPCODE_STACK_POP = (unsigned char)0x4,
OPCODE_ZERO_OPS_MASK = (unsigned char)0xf8,
OPCODE_NOP = (unsigned char)0x01,
OPCODE_HLT = (unsigned char)0x02,
OPCODE_RET = (unsigned char)0x03
} Opcode;
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