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Implement remaining rolls.

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This commit is contained in:
Thomas Harte
2023-10-13 22:03:54 -04:00
parent f45d8bcbdb
commit f1cba4eb78
2 changed files with 109 additions and 3 deletions
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94
InstructionSets/x86/Implementation/PerformImplementation.hpp
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@@ -1021,7 +1021,99 @@ inline void rcr(IntT &destination, uint8_t count, Status &status) {
status.set_from<Flag::Carry>(carry);
}
template <typename IntT>
inline void rol(IntT &destination, uint8_t count, Status &status) {
/*
(* ROL and ROR instructions *)
SIZE ← OperandSize
CASE (determine count) OF
SIZE = 8: tempCOUNT ← COUNT MOD 8;
SIZE = 16: tempCOUNT ← COUNT MOD 16;
SIZE = 32: tempCOUNT ← COUNT MOD 32;
ESAC;
*/
/*
(* ROL instruction operation *)
WHILE (tempCOUNT ≠ 0)
DO
tempCF ← MSB(DEST);
DEST ← (DEST * 2) + tempCF;
tempCOUNT ← tempCOUNT – 1;
OD;
ELIHW;
IF COUNT = 1
THEN OF ← MSB(DEST) XOR CF;
ELSE OF is undefined;
FI;
*/
/*
The CF flag contains the value of the bit shifted into it.
The OF flag is affected only for single- bit rotates (see “Description” above);
it is undefined for multi-bit rotates. The SF, ZF, AF, and PF flags are not affected.
*/
const auto temp_count = count & (Numeric::bit_size<IntT>() - 1);
if(!count) {
// TODO: is this 8086-specific? i.e. do the other x86s also exit without affecting flags when temp_count = 0?
return;
}
if(temp_count) {
destination =
(destination << temp_count) |
(destination >> (Numeric::bit_size<IntT>() - temp_count));
}
status.set_from<Flag::Carry>(destination & 1);
status.set_from<Flag::Overflow>(
((destination >> (Numeric::bit_size<IntT>() - 1)) ^ destination) & 1
);
}
template <typename IntT>
inline void ror(IntT &destination, uint8_t count, Status &status) {
/*
(* ROL and ROR instructions *)
SIZE ← OperandSize
CASE (determine count) OF
SIZE = 8: tempCOUNT ← COUNT MOD 8;
SIZE = 16: tempCOUNT ← COUNT MOD 16;
SIZE = 32: tempCOUNT ← COUNT MOD 32;
ESAC;
*/
/*
(* ROR instruction operation *)
WHILE (tempCOUNT ≠ 0)
DO
tempCF ← LSB(DEST);
DEST ← (DEST / 2) + (tempCF * 2^SIZE);
tempCOUNT ← tempCOUNT – 1;
OD;
ELIHW;
IF COUNT = 1
THEN OF ← MSB(DEST) XOR MSB - 1 (DEST);
ELSE OF is undefined;
FI;
*/
/*
The CF flag contains the value of the bit shifted into it.
The OF flag is affected only for single- bit rotates (see “Description” above);
it is undefined for multi-bit rotates. The SF, ZF, AF, and PF flags are not affected.
*/
const auto temp_count = count & (Numeric::bit_size<IntT>() - 1);
if(!count) {
// TODO: is this 8086-specific? i.e. do the other x86s also exit without affecting flags when temp_count = 0?
return;
}
if(temp_count) {
destination =
(destination >> temp_count) |
(destination << (Numeric::bit_size<IntT>() - temp_count));
}
status.set_from<Flag::Carry>(destination & Numeric::top_bit<IntT>());
status.set_from<Flag::Overflow>(
(destination ^ (destination << 1)) & Numeric::top_bit<IntT>()
);
}
}
template <
@@ -1185,6 +1277,8 @@ template <
case Operation::RCL: Primitive::rcl(destination(), shift_count(), status); break;
case Operation::RCR: Primitive::rcr(destination(), shift_count(), status); break;
case Operation::ROL: Primitive::rol(destination(), shift_count(), status); break;
case Operation::ROR: Primitive::ror(destination(), shift_count(), status); break;
case Operation::CLC: Primitive::clc(status); return;
case Operation::CLD: Primitive::cld(status); return;