Enrico Fraccaroli (Galfurian)
133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
/// @file fpu.h
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/// @brief Floating Point Unit (FPU).
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/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
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/// See LICENSE.md for details.
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/// @addtogroup devices Hardware Interfaces
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/// @brief Data structures and functions for managing hardware devices.
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/// @{
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/// @addtogroup fpu Floating Point Unit (FPU)
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/// @brief Device designed to carry out operations on floating-point numbers.
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/// @{
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#pragma once
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#include "stdint.h"
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/// @brief Environment information of floating point unit.
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typedef struct env87 {
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/// Control word (16bits).
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long en_cw;
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/// Status word (16bits).
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long en_sw;
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/// Tag word (16bits).
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long en_tw;
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/// Floating point instruction pointer.
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long en_fip;
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/// Floating code segment selector.
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unsigned short en_fcs;
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/// Opcode last executed (11 bits).
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unsigned short en_opcode;
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/// Floating operand offset.
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long en_foo;
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/// Floating operand segment selector.
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long en_fos;
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} env87;
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/// @brief Contents of each floating point accumulator.
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typedef struct fpacc87 {
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/// Easy to access bytes.
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unsigned char fp_bytes[10];
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} fpacc87;
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/// @brief Floating point context.
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typedef struct save87 {
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/// Floating point control/status.
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env87 sv_env;
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/// Accumulator contents, 0-7.
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fpacc87 sv_ac[8];
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/// Padding for (now unused) saved status word.
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unsigned char sv_pad0[4];
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/*
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* Bogus padding for emulators. Emulators should use their own
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* struct and arrange to store into this struct (ending here)
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* before it is inspected for ptracing or for core dumps. Some
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* emulators overwrite the whole struct. We have no good way of
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* knowing how much padding to leave. Leave just enough for the
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* GPL emulator's i387_union (176 bytes total).
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*/
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/// Padding used by emulators.
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unsigned char sv_pad[64];
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} save87;
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/// @brief Stores the XMM environment.
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typedef struct envxmm {
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/// Control word (16bits).
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uint16_t en_cw;
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/// Status word (16bits).
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uint16_t en_sw;
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/// Tag word (16bits).
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uint16_t en_tw;
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/// Opcode last executed (11 bits).
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uint16_t en_opcode;
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/// Floating point instruction pointer.
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uint32_t en_fip;
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/// Floating code segment selector.
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uint16_t en_fcs;
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/// Padding.
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uint16_t en_pad0;
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/// Floating operand offset.
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uint32_t en_foo;
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/// Floating operand segment selector.
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uint16_t en_fos;
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/// Padding.
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uint16_t en_pad1;
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/// SSE sontorol/status register.
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uint32_t en_mxcsr;
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/// Valid bits in mxcsr.
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uint32_t en_mxcsr_mask;
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} envxmm;
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/// @brief Contents of each SSE extended accumulator.
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typedef struct xmmacc {
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/// TODO: Comment.
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unsigned char xmm_bytes[16];
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} xmmacc;
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/// @brief Stores the XMM context.
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typedef struct savexmm {
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/// TODO: Comment.
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envxmm sv_env;
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/// TODO: Comment.
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struct {
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/// TODO: Comment.
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fpacc87 fp_acc;
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/// Padding.
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unsigned char fp_pad[6];
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} sv_fp[8];
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/// TODO: Comment.
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xmmacc sv_xmm[8];
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/// Padding.
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unsigned char sv_pad[224];
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} __attribute__((__aligned__(16))) savexmm;
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/// @brief Stores FPU registers details.
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typedef union savefpu {
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/// Stores the floating point context.
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save87 sv_87;
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/// Stores the XMM context.
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savexmm sv_xmm;
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} savefpu;
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/// @brief Called during a context switch to save the FPU registers status
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/// of the currently running thread.
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void switch_fpu();
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/// @brief Called during a context switch to load the FPU registers status
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/// of the currently running thread inside the FPU.
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void unswitch_fpu();
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/// @brief Enable the FPU context handling.
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/// @return 0 if fails, 1 if succeed.
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int fpu_install();
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/// @}
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/// @}
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