/**************************************************************************** * arch/x86/include/i486/arch.h * * Copyright (C) 2011 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /* This file should never be included directed but, rather, * only indirectly through nuttx/arch.h */ #ifndef __ARCH_X86_INCLUDE_I486_ARCH_H #define __ARCH_X86_INCLUDE_I486_ARCH_H /**************************************************************************** * Included Files ****************************************************************************/ #include #ifndef __ASSEMBLY__ # include #endif /**************************************************************************** * Definitions ****************************************************************************/ /* FLAGS bits */ #define X86_FLAGS_CF (1 << 0) /* Bit 0: Carry Flag */ /* Bit 1: Reserved */ #define X86_FLAGS_PF (1 << 2) /* Bit 2: Parity Flag */ /* Bit 3: Reserved */ #define X86_FLAGS_AF (1 << 4) /* Bit 4: Auxillary carry Flag */ /* Bit 5: Reserved */ #define X86_FLAGS_ZF (1 << 6) /* Bit 6: Zero Flag */ #define X86_FLAGS_SF (1 << 7) /* Bit 7: Sign Flag */ #define X86_FLAGS_TF (1 << 8) /* Bit 8: Trap Flag */ #define X86_FLAGS_IF (1 << 9) /* Bit 9: Interrupt Flag */ #define X86_FLAGS_DF (1 << 10) /* Bit 10: Direction Flag */ #define X86_FLAGS_OF (1 << 11) /* Bit 11: Overflow Flag */ #define X86_FLAGS_IOPL_SHIFT (12) /* Bits 12-13: IOPL mask (286+ only)*/ #define X86_FLAGS_IOPL_MASK (3 << X86_FLAGS_IOPL_SHIFT) #define X86_FLAGS_NT (1 << 14) /* Bit 14: Nested Task */ /* Bit 15: Reserved */ /* EFLAGS bits (Extend the basic FLAGS bit definitions) */ #define X86_EFLAGS_RF (1 << 16) /* Bit 16: Resume Flag (386+ only) */ #define X86_EFLAGS_VM (1 << 17) /* Bit 17: Virtual Mode (386+ only) */ #define X86_EFLAGS_AC (1 << 18) /* Bit 18: Alignment Check (486SX+ only) */ #define X86_EFLAGS_VIF (1 << 19) /* Bit 19: Virtual Interrupt Flag (Pentium+) */ #define X86_EFLAGS_VIP (1 << 20) /* Bit 20: Virtual Interrupt Pending (Pentium+) */ #define X86_EFLAGS_ID (1 << 21) /* Bit 21: CPUID detection flag (Pentium+) */ /**************************************************************************** * Public Types ****************************************************************************/ /* GDT data structures ****************************************************** * * The Global Descriptor Table or GDT is a data structure used by Intel x86- * family processors starting with the 80286 in order to define the * characteristics of the various memory areas used during program execution, * for example the base address, the size and access privileges like * executability and writability. These memory areas are called segments in * Intel terminology. */ /* This structure defines one segment */ struct gdt_entry_s { uint16_t lowlimit; /* The lower 16 bits of the limit */ uint16_t lowbase; /* The lower 16 bits of the base */ uint8_t midbase; /* The next 8 bits of the base */ uint8_t access; /* Access flags, determine ring segment can be used in */ uint8_t granularity; uint8_t hibase; /* The last 8 bits of the base */ } __attribute__((packed)); /* This structure refers to the array of GDT entries, and is in the format * required by the lgdt instruction. */ struct gdt_ptr_s { uint16_t limit; /* The upper 16 bits of all selector limits */ uint32_t base; /* The address of the first GDT entry */ } __attribute__((packed)); /* IDT data structures ****************************************************** * * The Interrupt Descriptor Table (IDT) is a data structure used by the x86 * architecture to implement an interrupt vector table. The IDT is used by the * processor to determine the correct response to interrupts and exceptions. */ struct idt_entry_s { uint16_t lobase; /* Lower 16-bits of vector address for interrupt */ uint16_t sel; /* Kernel segment selector */ uint8_t zero; /* This must always be zero */ uint8_t flags; /* (See documentation) */ uint16_t hibase; /* Upper 16-bits of vector address for interrupt */ } __attribute__((packed)); /* A struct describing a pointer to an array of interrupt handlers. This is * in a format suitable for giving to 'lidt'. */ struct idt_ptr_s { uint16_t limit; uint32_t base; /* The address of the first GDT entry */ } __attribute__((packed)); /**************************************************************************** * Inline functions ****************************************************************************/ #ifndef __ASSEMBLY__ /* Return stack pointer */ static inline uint32_t up_getsp() { uint32_t regval; asm volatile( "\tmovl %%esp, %0\n" : "=rm" (regval) : : "memory"); return regval; } /* Get segment registers */ static inline uint32_t up_getds() { uint32_t regval; asm volatile( "\tmov %%ds, %0\n" : "=rm" (regval) : : "memory"); return regval; } static inline uint32_t up_getcs() { uint32_t regval; asm volatile( "\tmov %%cs, %0\n" : "=rm" (regval) : : "memory"); return regval; } static inline uint32_t up_getss() { uint32_t regval; asm volatile( "\tmov %%ss, %0\n" : "=rm" (regval) : : "memory"); return regval; } /**************************************************************************** * Public Types ****************************************************************************/ /**************************************************************************** * Public Variables ****************************************************************************/ /**************************************************************************** * Public Function Prototypes ****************************************************************************/ #ifdef __cplusplus #define EXTERN extern "C" extern "C" { #else #define EXTERN extern #endif EXTERN void gdt_flush(uint32_t gdt_addr); EXTERN void idt_flush(uint32_t idt_addr); #undef EXTERN #ifdef __cplusplus } #endif #endif /* __ASSEMBLY__ */ #endif /* __ARCH_X86_INCLUDE_I486_ARCH_H */