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mirror of https://github.com/TomHarte/CLK.git synced 2024-06-26 10:29:31 +00:00

Add documentation.

This commit is contained in:
Thomas Harte 2023-11-04 22:22:50 -04:00
parent 5739862dbb
commit f96c33102a
2 changed files with 33 additions and 12 deletions

View File

@ -28,13 +28,14 @@ IntT *resolve(
IntT *immediate = nullptr
);
/// Calculates the absolute address for @c pointer given the registers and memory provided in @c context and taking any
/// referenced offset from @c instruction.
template <Source source, typename IntT, AccessType access, typename InstructionT, typename ContextT>
uint32_t address(
InstructionT &instruction,
DataPointer pointer,
ContextT &context
) {
// TODO: non-word indexes and bases.
if constexpr (source == Source::DirectAddress) {
return instruction.offset();
}
@ -53,6 +54,9 @@ uint32_t address(
return address + *resolve<uint16_t, access>(instruction, pointer.base(), pointer, context);
}
/// @returns a pointer to the contents of the register identified by the combination of @c IntT and @c Source if any;
/// @c nullptr otherwise. @c access is currently unused but is intended to provide the hook upon which updates to
/// segment registers can be tracked for protected modes.
template <typename IntT, AccessType access, Source source, typename ContextT>
IntT *register_(ContextT &context) {
static constexpr bool supports_dword = is_32bit(ContextT::model);
@ -103,10 +107,21 @@ IntT *register_(ContextT &context) {
else if constexpr (std::is_same_v<IntT, uint8_t>) { return &context.registers.bh(); }
else { return nullptr; }
// Segment registers are always 16-bit.
case Source::ES: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.es(); else return nullptr;
case Source::CS: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.cs(); else return nullptr;
case Source::SS: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.ss(); else return nullptr;
case Source::DS: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.ds(); else return nullptr;
// 16-bit models don't have FS and GS.
case Source::FS: if constexpr (is_32bit(ContextT::model) && std::is_same_v<IntT, uint16_t>) return &context.registers.fs(); else return nullptr;
case Source::GS: if constexpr (is_32bit(ContextT::model) && std::is_same_v<IntT, uint16_t>) return &context.registers.gs(); else return nullptr;
default: return nullptr;
}
}
///Obtains the address described by @c pointer from @c instruction given the registers and memory as described by @c context.
template <typename IntT, AccessType access, typename InstructionT, typename ContextT>
uint32_t address(
InstructionT &instruction,
@ -131,6 +146,13 @@ uint32_t address(
}
}
/// Obtain a pointer to the value desribed by @c source, which is one of those named by @c pointer, using @c instruction and @c context
/// for offsets, registers and memory contents.
///
/// If @c source is Source::None then @c none is returned.
///
/// If @c source is Source::Immediate then the appropriate portion of @c instrucion's operand
/// is copied to @c *immediate and @c immediate is returned.
template <typename IntT, AccessType access, typename InstructionT, typename ContextT>
IntT *resolve(
InstructionT &instruction,
@ -146,6 +168,7 @@ IntT *resolve(
// * otherwise return the appropriate value.
uint32_t target_address;
switch(source) {
// Defer all register accesses to the register-specific lookup.
case Source::eAX: return register_<IntT, access, Source::eAX>(context);
case Source::eCX: return register_<IntT, access, Source::eCX>(context);
case Source::eDX: return register_<IntT, access, Source::eDX>(context);
@ -154,23 +177,19 @@ IntT *resolve(
case Source::eBPorCH: return register_<IntT, access, Source::eBPorCH>(context);
case Source::eSIorDH: return register_<IntT, access, Source::eSIorDH>(context);
case Source::eDIorBH: return register_<IntT, access, Source::eDIorBH>(context);
case Source::ES: return register_<IntT, access, Source::ES>(context);
case Source::CS: return register_<IntT, access, Source::CS>(context);
case Source::SS: return register_<IntT, access, Source::SS>(context);
case Source::DS: return register_<IntT, access, Source::DS>(context);
case Source::FS: return register_<IntT, access, Source::FS>(context);
case Source::GS: return register_<IntT, access, Source::GS>(context);
// Segment registers are always 16-bit.
case Source::ES: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.es(); else return nullptr;
case Source::CS: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.cs(); else return nullptr;
case Source::SS: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.ss(); else return nullptr;
case Source::DS: if constexpr (std::is_same_v<IntT, uint16_t>) return &context.registers.ds(); else return nullptr;
// 16-bit models don't have FS and GS.
case Source::FS: if constexpr (is_32bit(ContextT::model) && std::is_same_v<IntT, uint16_t>) return &context.registers.fs(); else return nullptr;
case Source::GS: if constexpr (is_32bit(ContextT::model) && std::is_same_v<IntT, uint16_t>) return &context.registers.gs(); else return nullptr;
case Source::None: return none;
case Source::Immediate:
*immediate = instruction.operand();
return immediate;
case Source::None: return none;
case Source::Indirect:
target_address = address<Source::Indirect, IntT, access>(instruction, pointer, context);
break;

View File

@ -126,7 +126,9 @@ struct Memory {
tags[address] = Tag::AccessExpected;
}
//
// Preauthorisation call-ins.
//
void preauthorise_stack_write(uint32_t length) {
uint16_t sp = registers_.sp_;
while(length--) {