;============================================================================= ; 386p.inc - The 386 Protected Mode structures and definitions. ; ; Copyright (C) 1992-93, Dennis Marer File created: 12/21/92 ; Last modified: 1/27/93 ; ; Description: ; This file defines the structures and equates for use in setting up and ; using the 386 Protected Mode. This includes all types of descriptors, ; Task State Segments (TSS), and so on. Note that the 286 versions of ; each of these are not supported. ; ; Portability: ; Requires Turbo Assembler 1.0 (TASM) or better to be assembled. ; Dependent on a 386 or later microprocessor. ; No other platform or hardware dependencies. ; ; Modifications: ; DPM, 1/27/93 Finished the first revision of this file. ;============================================================================= ;=============================== Descriptors ================================= ;----------------------------------------------------------------------------- ; seg_descr/gate_descr - Normal segment and gate descriptor structures, each ; of which has a slightly different format. In each, the flags found in ; the 'limit_16' field can be setup and masked using the LIM_ macros, ; and the flags and values in the 'access' field with the AC*_ macros. ; ; Normal code or data segment, TSS, or LDT descriptor: ; ; 31 15 0 ; +-------------------------------+-------------------------------+ ; | Base | Limit | 0 ; | 15-0 | 15-0 | ; +---------------+-+-+-+-+-------+-+-+-+-+-+-+-+-+---------------+ ; | Base |G|D|0|0| Limit |P|DPL|S| see | Base | +4 ; | 31-24 | |B| | | 19-16 | | | | below | 23-16 | ; +---------------+-+-+-+-+-------+-+-+-+-+-+-+-+-+---------------+ ; ; TSS or LDT segment (S=0): Normal segment (S=1): ; +---+---+---+---+ +---+----+---+---+ ; | Type | | E |ED/C|W/R| A | ; +---+---+---+---+ +---+----+---+---+ ; ; All system gate descriptors: ; ; 31 15 0 ; +-------------------------------+-------------------------------+ ; | Selector | Offset | 0 ; | | 15-0 | ; +-------------------------------+-+---+-+-+-+-+-+-+-+-+---------+ ; | Offset |P|DPL|0| Type |0|0|0| Words | +4 ; | 31-16 | | | | | | | | 4-0 | ; +-------------------------------+-+---+-+-+-+-+-+-+-+-+---------+ ; ;----------------------------------------------------------------------------- seg_descr struc limit_0 dw 0 ; Segment limit, bits 15-0 base_0 dw 0 ; Segment base, bits 15-0 base_16 db 0 ; Segment base, bits 23-16 access db 0 ; Access rights limit_16 db 0 ; Segment limit, bits 19-16 base_24 db 0 ; Segment base, bits 31-24 seg_descr ends gate_descr struc offset_0 dw 0 ; Offset, bits 15-0 selector dw 0 ; Selector value words db 0 ; Word count, bits 4-0 access db 0 ; Access rights offset_16 dw 0 ; Offset, bits 31-16 gate_descr ends ;----------------------------------------------------------------------------- ; The following equates are used to create and examine descriptors. The ; LIM_ equates apply to the 'limit_16' field. The AC_ equates apply to ; all descriptors with an 'access' field. The ACD_ equates apply only to ; data descriptors, where the ACC_ equates apply to code descriptors. ; Finally, the ACT_ equates define the system descriptor types. (Anything ; except code and data descriptors.) ;----------------------------------------------------------------------------- LIM_PAGE equ 080h ; Page (byte) granular LIM_32BIT equ 040h ; 32-bit (16-bit) segment LIM_LIMIT equ 00Fh ; Limit 16-19 mask AC_MAPPED equ 080h ; Segment is (not) mapped AC_DPL equ 060h ; Descriptor priority mask AC_DPL0 equ 000h ; Descriptor priority level 0 AC_DPL1 equ 020h ; Descriptor priority level 1 AC_DPL2 equ 040h ; Descriptor priority level 2 AC_DPL3 equ 060h ; Descriptor priority level 3 AC_USER equ 010h ; User (code or data) task AC_CODE equ 008h ; Code (data) segment AC_ACCESS equ 001h ; Segment was (not) accessed ACD_DOWN equ 004h ; Data expands down (up) ACD_WRITE equ 002h ; Data (not) writeable ACC_CONFORM equ 004h ; Code (not) conforming ACC_READ equ 002h ; Code (not) readable ACT_MASK equ 00Fh ; System descriptor types ACT_LDT equ 002h ; Local descriptor table type ACT_TASK equ 005h ; Task gate type ACT_A386 equ 009h ; 386 TSS types ACT_B386 equ 00Bh ACT_CALL386 equ 00Ch ; 386 gate types ACT_INT386 equ 00Eh ACT_TRAP386 equ 00Fh ;=========================== Task State Segments ============================= ;----------------------------------------------------------------------------- ; tss386 - A 386 Protected Mode Task State Segment. Any amount of data may ; exist between the I/O bitmap offset value and the I/O bitmap, defineable ; by the operating system. Here, no extra memory is assumed, and the ; I/O bitmap is fully defined (8192 bytes) for full access. ;----------------------------------------------------------------------------- tss386 struc t3BackLink dw ? ; Previous TSS backlink dw 0 ; Reserved t3ESP0 dd ? ; Stack 0 pointer (CPL=0) t3SS0 dw ? ; Stack 0 segment dw 0 ; Reserved t3ESP1 dd ? ; Stack 1 pointer (CPL=1) t3SS1 dw ? ; Stack 1 segment dw 0 ; Reserved t3ESP2 dd ? ; Stack 2 pointer (CPL=2) t3SS2 dw ? ; Stack 2 segment dw 0 ; Reserved t3CR3 dd ? ; CR3 t3EIP dd ? ; Instruction pointer t3EFlags dd ? ; Extended flags t3EAX dd ? ; Task general registers t3ECX dd ? t3EDX dd ? t3EBX dd ? t3ESP dd ? t3EBP dd ? t3ESI dd ? t3EDI dd ? t3ES dw ? ; Task segment registers dw 0 ; Reserved t3CS dw ? dw 0 ; Reserved t3SS dw ? dw 0 ; Reserved t3DS dw ? dw 0 ; Reserved t3FS dw ? dw 0 ; Reserved t3GS dw ? dw 0 ; Reserved t3LDT dw ? ; Task local descriptor table dw 0 ; Reserved t3Trap dw ? ; Holds debug trap bit (T) t3IOOfs dw 2+$-tss386 ; I/O map address offset t3IOMap db 2000h dup (000h) ; Give full I/O access db 0FFh ; Terminator tss386 ends