--- /dev/null
+; -*- fundamental -*- (asm-mode sucks)
+; $Id$
+; ****************************************************************************
+;
+; memdisk.asm
+;
+; A program to emulate an INT 13h disk BIOS from a "disk" in extended
+; memory.
+;
+; Copyright (C) 2001 H. Peter Anvin
+;
+; This program is free software; you can redistribute it and/or modify
+; it under the terms of the GNU General Public License as published by
+; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
+; USA; either version 2 of the License, or (at your option) any later
+; version; incorporated herein by reference.
+;
+; ****************************************************************************
+
+ org 0h
+
+MyStack equ 1024
+
+ ; Parameter registers definition; this is the definition
+ ; of the stack frame.
+%define P_EAX dword [bp+28]
+%define P_AX word [bp+28]
+%define P_AL byte [bp+28]
+%define P_AH byte [bp+29]
+%define P_ECX dword [bp+24]
+%define P_CX word [bp+24]
+%define P_CL byte [bp+24]
+%define P_CH byte [bp+25]
+%define P_EDX dword [bp+20]
+%define P_DX word [bp+20]
+%define P_DL byte [bp+20]
+%define P_DH byte [bp+21]
+%define P_EBX dword [bp+16]
+%define P_BX word [bp+16]
+%define P_BL byte [bp+16]
+%define P_BH byte [bp+17]
+%define P_EBP dword [bp+8]
+%define P_BP word [bp+8]
+%define P_ESI dword [bp+4]
+%define P_SI word [bp+4]
+%define P_EDI dword [bp]
+%define P_DI word [bp]
+
+ section .text
+Int13Start:
+ ; See if DL points to our class of device (FD, HD)
+ push dx
+ xor dl,[cs:DriveNo]
+ pop dx
+ js .nomatch ; If SF=0, we have a match here
+ cmp dl,[cs:DriveNo]
+ je .our_drive
+ jb .nomatch ; Drive < Our drive
+ dec dl ; Drive > Our drive, adjust drive #
+.nomatch:
+ jmp far [OldInt13]
+
+.our_drive:
+ mov [cs:Stack],sp
+ mov [cs:SavedAX],ax
+ mov ax,ss
+ mov [cs:Stack+2],ax
+ mov ax,cs
+ mov ss,ax
+ mov sp,MyStack
+ push ds
+ push es
+ mov ds,ax
+ mov es,ax
+ mov ax,[SavedAX]
+ pushad
+ mov bp,sp
+ cmp ah,Int13FuncsMax
+ jae Invalid
+ xor al,al ; AL = 0 is standard entry condition
+ mov di,ax
+ shr di,7
+ call [Int13Funcs+di]
+
+Done: ; Standard routine for return
+ mov [LastStatus],ah
+ mov P_AX,ax
+ cmp ah,1
+ setnb al ; AL <- (AH > 0) ? 1 : 0 (CF)
+ lds bx,[Stack] ; DS:BX <- Old stack pointer
+ mov [bx+4],al ; Low byte of old FLAGS -> arithmetric flags
+ popad
+ pop es
+ pop ds
+ lss sp,[cs:Stack]
+ iret
+
+Reset:
+ ; Reset affects multiple drives, so we need to pass it on
+ pop ax ; Drop return address
+ mov [LastStatus], byte 0
+ popad
+ pop es
+ pop ds
+ lss sp,[cs:Stack]
+ and dl,80h ; Clear all but the type bit
+ jmp far [OldInt13]
+
+GetStatus:
+ mov ah,[LastStatus] ; Copy last status
+ ret
+
+CheckIfReady:
+Recalibrate:
+ xor ah,ah ; Always successful
+ ret
+
+Read:
+Write:
+Verify:
+Format:
+GetParms:
+InitWithParms:
+Seek:
+GetDriveType:
+DetectChange:
+
+Invalid:
+ mov ah,01h ; Unsupported function
+ ret
+
+ section .data
+Int13Funcs dw Reset ; 00h - RESET
+ dw GetStatus ; 01h - GET STATUS
+ dw Read ; 02h - READ
+ dw Write ; 03h - WRITE
+ dw Verify ; 04h - VERIFY
+ dw Format ; 05h - FORMAT TRACK
+ dw Format ; 06h - FORMAT TRACK AND SET BAD FLAGS
+ dw Format ; 07h - FORMAT DRIVE AT TRACK
+ dw GetParms ; 08h - GET PARAMETERS
+ dw InitWithParms ; 09h - INITIALIZE CONTROLLER WITH DRIVE PARAMETERS
+ dw Invalid ; 0Ah
+ dw Invalid ; 0Bh
+ dw Seek ; 0Ch - SEEK TO CYLINDER
+ dw Reset ; 0Dh - RESET HARD DISKS
+ dw Invalid ; 0Eh
+ dw Invalid ; 0Fh
+ dw CheckIfReady ; 10h - CHECK IF READY
+ dw Recalibrate ; 11h - RECALIBRATE
+ dw Invalid ; 12h
+ dw Invalid ; 13h
+ dw Invalid ; 14h
+ dw GetDriveType ; 15h - GET DRIVE TYPE
+ dw DetectChange ; 16h - DETECT DRIVE CHANGE
+Int13FuncsEnd equ $
+Int13FuncsMax equ (Int13FuncsEnd-Int13Funcs) >> 1
+
+DriveNo db 0 ; Our drive number
+LastStatus db 0 ; Last return status
+
+ section .bss
+OldInt13 resd 1 ; INT 13h in chain
+Stack resd 1 ; Saved SS:SP on invocation
+SavedAX resw 1 ; AX saved during initialization
+
+
--- /dev/null
+; -*- fundamental -*- (asm-mode sucks)
+; $Id$
+; ****************************************************************************
+;
+; memdisk.asm
+;
+; A program to emulate an INT 13h disk BIOS from a "disk" in extended
+; memory.
+;
+; Copyright (C) 2001 H. Peter Anvin
+;
+; This program is free software; you can redistribute it and/or modify
+; it under the terms of the GNU General Public License as published by
+; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
+; USA; either version 2 of the License, or (at your option) any later
+; version; incorporated herein by reference.
+;
+; ****************************************************************************
+
+ org 0h
+
+MyStack equ 1024
+
+ ; Parameter registers definition; this is the definition
+ ; of the stack frame.
+%define P_EAX dword [bp+28]
+%define P_AX word [bp+28]
+%define P_AL byte [bp+28]
+%define P_AH byte [bp+29]
+%define P_ECX dword [bp+24]
+%define P_CX word [bp+24]
+%define P_CL byte [bp+24]
+%define P_CH byte [bp+25]
+%define P_EDX dword [bp+20]
+%define P_DX word [bp+20]
+%define P_DL byte [bp+20]
+%define P_DH byte [bp+21]
+%define P_EBX dword [bp+16]
+%define P_BX word [bp+16]
+%define P_BL byte [bp+16]
+%define P_BH byte [bp+17]
+%define P_EBP dword [bp+8]
+%define P_BP word [bp+8]
+%define P_ESI dword [bp+4]
+%define P_SI word [bp+4]
+%define P_EDI dword [bp]
+%define P_DI word [bp]
+
+ section .text
+Int13Start:
+ ; See if DL points to our class of device (FD, HD)
+ push dx
+ xor dl,[cs:DriveNo]
+ pop dx
+ js .nomatch ; If SF=0, we have a match here
+ cmp dl,[cs:DriveNo]
+ je .our_drive
+ jb .nomatch ; Drive < Our drive
+ dec dl ; Drive > Our drive, adjust drive #
+.nomatch:
+ jmp far [OldInt13]
+
+.our_drive:
+ mov [cs:Stack],sp
+ mov [cs:SavedAX],ax
+ mov ax,ss
+ mov [cs:Stack+2],ax
+ mov ax,cs
+ mov ss,ax
+ mov sp,MyStack
+ push ds
+ push es
+ mov ds,ax
+ mov es,ax
+ mov ax,[SavedAX]
+ pushad
+ mov bp,sp
+ cmp ah,Int13FuncsMax
+ jae Invalid
+ xor al,al ; AL = 0 is standard entry condition
+ mov di,ax
+ shr di,7
+ call [Int13Funcs+di]
+
+Done: ; Standard routine for return
+ mov [LastStatus],ah
+ mov P_AX,ax
+ cmp ah,1
+ setnb al ; AL <- (AH > 0) ? 1 : 0 (CF)
+ lds bx,[Stack] ; DS:BX <- Old stack pointer
+ mov [bx+4],al ; Low byte of old FLAGS -> arithmetric flags
+ popad
+ pop es
+ pop ds
+ lss sp,[cs:Stack]
+ iret
+
+Reset:
+ ; Reset affects multiple drives, so we need to pass it on
+ pop ax ; Drop return address
+ mov [LastStatus], byte 0
+ popad
+ pop es
+ pop ds
+ lss sp,[cs:Stack]
+ and dl,80h ; Clear all but the type bit
+ jmp far [OldInt13]
+
+GetStatus:
+ mov ah,[LastStatus] ; Copy last status
+ ret
+
+CheckIfReady:
+Recalibrate:
+ xor ah,ah ; Always successful
+ ret
+
+Read:
+Write:
+Verify:
+Format:
+GetParms:
+InitWithParms:
+Seek:
+GetDriveType:
+DetectChange:
+
+Invalid:
+ mov ah,01h ; Unsupported function
+ ret
+
+ section .data
+Int13Funcs dw Reset ; 00h - RESET
+ dw GetStatus ; 01h - GET STATUS
+ dw Read ; 02h - READ
+ dw Write ; 03h - WRITE
+ dw Verify ; 04h - VERIFY
+ dw Format ; 05h - FORMAT TRACK
+ dw Format ; 06h - FORMAT TRACK AND SET BAD FLAGS
+ dw Format ; 07h - FORMAT DRIVE AT TRACK
+ dw GetParms ; 08h - GET PARAMETERS
+ dw InitWithParms ; 09h - INITIALIZE CONTROLLER WITH DRIVE PARAMETERS
+ dw Invalid ; 0Ah
+ dw Invalid ; 0Bh
+ dw Seek ; 0Ch - SEEK TO CYLINDER
+ dw Reset ; 0Dh - RESET HARD DISKS
+ dw Invalid ; 0Eh
+ dw Invalid ; 0Fh
+ dw CheckIfReady ; 10h - CHECK IF READY
+ dw Recalibrate ; 11h - RECALIBRATE
+ dw Invalid ; 12h
+ dw Invalid ; 13h
+ dw Invalid ; 14h
+ dw GetDriveType ; 15h - GET DRIVE TYPE
+ dw DetectChange ; 16h - DETECT DRIVE CHANGE
+Int13FuncsEnd equ $
+Int13FuncsMax equ (Int13FuncsEnd-Int13Funcs) >> 1
+
+DriveNo db 0 ; Our drive number
+LastStatus db 0 ; Last return status
+
+ section .bss
+OldInt13 resd 1 ; INT 13h in chain
+Stack resd 1 ; Saved SS:SP on invocation
+SavedAX resw 1 ; AX saved during initialization
+
+
projects / profile / ivi / syslinux.git / commitdiff