mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-26 23:52:26 +00:00
363 lines
9.7 KiB
C++
363 lines
9.7 KiB
C++
//
|
||
// Arithmetic.hpp
|
||
// Clock Signal
|
||
//
|
||
// Created by Thomas Harte on 08/11/2023.
|
||
// Copyright © 2023 Thomas Harte. All rights reserved.
|
||
//
|
||
|
||
#pragma once
|
||
|
||
#include "../AccessType.hpp"
|
||
#include "../Interrupts.hpp"
|
||
#include "../Perform.hpp"
|
||
|
||
#include "../../../Numeric/Carry.hpp"
|
||
|
||
namespace InstructionSet::x86::Primitive {
|
||
|
||
template <bool with_carry, typename IntT, typename ContextT>
|
||
void add(
|
||
modify_t<IntT> destination,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
DEST ← DEST + SRC [+ CF];
|
||
*/
|
||
/*
|
||
The OF, SF, ZF, AF, CF, and PF flags are set according to the result.
|
||
*/
|
||
const IntT result = destination + source + (with_carry ? context.flags.template carry_bit<IntT>() : 0);
|
||
|
||
context.flags.template set_from<Flag::Carry>(
|
||
Numeric::carried_out<true, Numeric::bit_size<IntT>() - 1>(destination, source, result));
|
||
context.flags.template set_from<Flag::AuxiliaryCarry>(
|
||
Numeric::carried_in<4>(destination, source, result));
|
||
context.flags.template set_from<Flag::Overflow>(
|
||
Numeric::overflow<true, IntT>(destination, source, result));
|
||
|
||
context.flags.template set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(result);
|
||
|
||
destination = result;
|
||
}
|
||
|
||
template <bool with_borrow, AccessType destination_type, typename IntT, typename ContextT>
|
||
void sub(
|
||
access_t<IntT, destination_type> destination,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
DEST ← DEST - (SRC [+ CF]);
|
||
*/
|
||
/*
|
||
The OF, SF, ZF, AF, CF, and PF flags are set according to the result.
|
||
*/
|
||
const IntT result = destination - source - (with_borrow ? context.flags.template carry_bit<IntT>() : 0);
|
||
|
||
context.flags.template set_from<Flag::Carry>(
|
||
Numeric::carried_out<false, Numeric::bit_size<IntT>() - 1>(destination, source, result));
|
||
context.flags.template set_from<Flag::AuxiliaryCarry>(
|
||
Numeric::carried_in<4>(destination, source, result));
|
||
context.flags.template set_from<Flag::Overflow>(
|
||
Numeric::overflow<false, IntT>(destination, source, result));
|
||
|
||
context.flags.template set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(result);
|
||
|
||
if constexpr (is_writeable(destination_type)) {
|
||
destination = result;
|
||
}
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void test(
|
||
read_t<IntT> destination,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
TEMP ← SRC1 AND SRC2;
|
||
SF ← MSB(TEMP);
|
||
IF TEMP = 0
|
||
THEN ZF ← 0;
|
||
ELSE ZF ← 1;
|
||
FI:
|
||
PF ← BitwiseXNOR(TEMP[0:7]);
|
||
CF ← 0;
|
||
OF ← 0;
|
||
*/
|
||
/*
|
||
The OF and CF flags are cleared to 0.
|
||
The SF, ZF, and PF flags are set according to the result (see the “Operation” section above).
|
||
The state of the AF flag is undefined.
|
||
*/
|
||
const IntT result = destination & source;
|
||
|
||
context.flags.template set_from<Flag::Carry, Flag::Overflow>(0);
|
||
context.flags.template set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(result);
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void mul(
|
||
modify_t<IntT> destination_high,
|
||
modify_t<IntT> destination_low,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
IF byte operation
|
||
THEN
|
||
AX ← AL * SRC
|
||
ELSE (* word or doubleword operation *)
|
||
IF OperandSize = 16 THEN
|
||
DX:AX ← AX * SRC
|
||
ELSE (* OperandSize = 32 *)
|
||
EDX:EAX ← EAX * SRC
|
||
FI;
|
||
*/
|
||
/*
|
||
The OF and CF flags are cleared to 0 if the upper half of the result is 0;
|
||
otherwise, they are set to 1. The SF, ZF, AF, and PF flags are undefined.
|
||
*/
|
||
destination_high = (destination_low * source) >> (8 * sizeof(IntT));
|
||
destination_low *= source;
|
||
context.flags.template set_from<Flag::Overflow, Flag::Carry>(destination_high);
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void imul(
|
||
modify_t<IntT> destination_high,
|
||
modify_t<IntT> destination_low,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
(as modified by https://www.felixcloutier.com/x86/daa ...)
|
||
|
||
IF (OperandSize = 8)
|
||
THEN
|
||
AX ← AL ∗ SRC (* signed multiplication *)
|
||
IF (AX = SignExtend(AL))
|
||
THEN CF = 0; OF = 0;
|
||
ELSE CF = 1; OF = 1;
|
||
FI;
|
||
ELSE IF OperandSize = 16
|
||
THEN
|
||
DX:AX ← AX ∗ SRC (* signed multiplication *)
|
||
IF (DX:AX = SignExtend(AX))
|
||
THEN CF = 0; OF = 0;
|
||
ELSE CF = 1; OF = 1;
|
||
FI;
|
||
ELSE (* OperandSize = 32 *)
|
||
EDX:EAX ← EAX ∗ SRC (* signed multiplication *)
|
||
IF (EDX:EAX = SignExtend(EAX))
|
||
THEN CF = 0; OF = 0;
|
||
ELSE CF = 1; OF = 1;
|
||
FI;
|
||
FI;
|
||
*/
|
||
using sIntT = typename std::make_signed<IntT>::type;
|
||
destination_high = IntT((sIntT(destination_low) * sIntT(source)) >> (8 * sizeof(IntT)));
|
||
destination_low = IntT(sIntT(destination_low) * sIntT(source));
|
||
|
||
const auto sign_extension = (destination_low & Numeric::top_bit<IntT>()) ? IntT(~0) : 0;
|
||
context.flags.template set_from<Flag::Overflow, Flag::Carry>(destination_high != sign_extension);
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void div(
|
||
modify_t<IntT> destination_high,
|
||
modify_t<IntT> destination_low,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
IF SRC = 0
|
||
THEN #DE; (* divide error *)
|
||
FI;
|
||
IF OperandSize = 8 (* word/byte operation *)
|
||
THEN
|
||
temp ← AX / SRC;
|
||
IF temp > FFH
|
||
THEN #DE; (* divide error *) ;
|
||
ELSE
|
||
AL ← temp;
|
||
AH ← AX MOD SRC;
|
||
FI;
|
||
ELSE
|
||
IF OperandSize = 16 (* doubleword/word operation *)
|
||
THEN
|
||
temp ← DX:AX / SRC;
|
||
IF temp > FFFFH
|
||
THEN #DE; (* divide error *) ;
|
||
ELSE
|
||
AX ← temp;
|
||
DX ← DX:AX MOD SRC;
|
||
FI;
|
||
ELSE (* quadword/doubleword operation *)
|
||
temp ← EDX:EAX / SRC;
|
||
IF temp > FFFFFFFFH
|
||
THEN #DE; (* divide error *) ;
|
||
ELSE
|
||
EAX ← temp;
|
||
EDX ← EDX:EAX MOD SRC;
|
||
FI;
|
||
FI;
|
||
FI;
|
||
*/
|
||
/*
|
||
The CF, OF, SF, ZF, AF, and PF flags are undefined.
|
||
*/
|
||
if(!source) {
|
||
interrupt(Interrupt::DivideError, context);
|
||
return;
|
||
}
|
||
|
||
// TEMPORARY HACK. Will not work with DWords.
|
||
const uint32_t dividend = uint32_t((destination_high << (8 * sizeof(IntT))) + destination_low);
|
||
const auto result = dividend / source;
|
||
if(IntT(result) != result) {
|
||
interrupt(Interrupt::DivideError, context);
|
||
return;
|
||
}
|
||
|
||
destination_low = IntT(result);
|
||
destination_high = dividend % source;
|
||
}
|
||
|
||
template <bool invert, typename IntT, typename ContextT>
|
||
void idiv(
|
||
modify_t<IntT> destination_high,
|
||
modify_t<IntT> destination_low,
|
||
read_t<IntT> source,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
IF SRC = 0
|
||
THEN #DE; (* divide error *)
|
||
FI;
|
||
IF OperandSize = 8 (* word/byte operation *)
|
||
THEN
|
||
temp ← AX / SRC; (* signed division *)
|
||
IF (temp > 7FH) OR (temp < 80H) (* if a positive result is greater than 7FH or a negative result is less than 80H *)
|
||
THEN #DE; (* divide error *) ;
|
||
ELSE
|
||
AL ← temp;
|
||
AH ← AX MOD SRC;
|
||
FI;
|
||
ELSE
|
||
IF OperandSize = 16 (* doubleword/word operation *)
|
||
THEN
|
||
temp ← DX:AX / SRC; (* signed division *)
|
||
IF (temp > 7FFFH) OR (temp < 8000H) (* if a positive result is greater than 7FFFH or a negative result is less than 8000H *)
|
||
THEN #DE; (* divide error *) ;
|
||
ELSE
|
||
AX ← temp;
|
||
DX ← DX:AX MOD SRC;
|
||
FI;
|
||
ELSE (* quadword/doubleword operation *)
|
||
temp ← EDX:EAX / SRC; (* signed division *)
|
||
IF (temp > 7FFFFFFFH) OR (temp < 80000000H) (* if a positive result is greater than 7FFFFFFFH or a negative result is less than 80000000H *)
|
||
THEN #DE; (* divide error *) ;
|
||
ELSE
|
||
EAX ← temp;
|
||
EDX ← EDX:EAX MOD SRC;
|
||
FI;
|
||
FI;
|
||
FI;
|
||
*/
|
||
/*
|
||
The CF, OF, SF, ZF, AF, and PF flags are undefined.
|
||
*/
|
||
if(!source) {
|
||
interrupt(Interrupt::DivideError, context);
|
||
return;
|
||
}
|
||
|
||
// TEMPORARY HACK. Will not work with DWords.
|
||
using sIntT = typename std::make_signed<IntT>::type;
|
||
const int32_t dividend = (sIntT(destination_high) << (8 * sizeof(IntT))) + destination_low;
|
||
auto result = dividend / sIntT(source);
|
||
|
||
// An 8086 quirk: rep IDIV performs an IDIV that switches the sign on its result,
|
||
// due to reuse of an internal flag.
|
||
if constexpr (invert) {
|
||
result = -result;
|
||
}
|
||
|
||
if(sIntT(result) != result) {
|
||
interrupt(Interrupt::DivideError, context);
|
||
return;
|
||
}
|
||
|
||
destination_low = IntT(result);
|
||
destination_high = IntT(dividend % sIntT(source));
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void inc(
|
||
modify_t<IntT> destination,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
DEST ← DEST + 1;
|
||
*/
|
||
/*
|
||
The CF flag is not affected.
|
||
The OF, SF, ZF, AF, and PF flags are set according to the result.
|
||
*/
|
||
++destination;
|
||
|
||
context.flags.template set_from<Flag::Overflow>(destination == Numeric::top_bit<IntT>());
|
||
context.flags.template set_from<Flag::AuxiliaryCarry>(((destination - 1) ^ destination) & 0x10);
|
||
context.flags.template set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void dec(
|
||
modify_t<IntT> destination,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
DEST ← DEST - 1;
|
||
*/
|
||
/*
|
||
The CF flag is not affected.
|
||
The OF, SF, ZF, AF, and PF flags are set according to the result.
|
||
*/
|
||
context.flags.template set_from<Flag::Overflow>(destination == Numeric::top_bit<IntT>());
|
||
|
||
--destination;
|
||
|
||
context.flags.template set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
|
||
context.flags.template set_from<Flag::AuxiliaryCarry>(((destination + 1) ^ destination) & 0x10);
|
||
}
|
||
|
||
template <typename IntT, typename ContextT>
|
||
void neg(
|
||
modify_t<IntT> destination,
|
||
ContextT &context
|
||
) {
|
||
/*
|
||
IF DEST = 0
|
||
THEN CF ← 0
|
||
ELSE CF ← 1;
|
||
FI;
|
||
DEST ← –(DEST)
|
||
*/
|
||
/*
|
||
The CF flag cleared to 0 if the source operand is 0; otherwise it is set to 1.
|
||
The OF, SF, ZF, AF, and PF flags are set according to the result.
|
||
*/
|
||
context.flags.template set_from<Flag::AuxiliaryCarry>(Numeric::carried_in<4>(IntT(0), destination, IntT(-destination)));
|
||
|
||
destination = -destination;
|
||
|
||
context.flags.template set_from<Flag::Carry>(destination);
|
||
context.flags.template set_from<Flag::Overflow>(destination == Numeric::top_bit<IntT>());
|
||
context.flags.template set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
|
||
}
|
||
|
||
}
|