Embedded BIOSTM 4.1 The Full-Featured BIOS for Embedded Systems and Consumer Electronics* BIOS User’s Manual with BIOS Interrupt Reference Copyright (C) 1990-1998 General Software, Inc. All rights reserved. TABLE OF CONTENTS KEY EMBEDDED BIOS CONCEPTS ................................................................................................ 7 1.1 ARCHITECTURAL OVERVIEW .......................................................................................................7 1.1.1 MEMORY MODEL.....................................................................................................................8 1.1.1.1 The Interrupt Vector Table.................................................................................................8 1.1.1.2 The BIOS Data Area..........................................................................................................8 1.1.1.3 Free Low RAM..................................................................................................................8 1.1.1.4 The Extended BIOS Data Area...........................................................................................9 1.1.1.5 Expanded Memory.............................................................................................................9 1.1.1.6 Video ROM Extensions......................................................................................................9 1.1.1.7 Other ROM Extensions......................................................................................................9 1.1.1.8 The System ROM ............................................................................................................10 1.1.1.9 Extended Memory............................................................................................................10 1.1.1.10 CMOS Memory .............................................................................................................10 1.1.2 INTERRUPT MODEL ................................................................................................................10 1.1.2.1 BIOS Service Interrupts ...................................................................................................12 1.1.2.1.1 INT 10h, Video Services............................................................................................12 1.1.2.1.2 INT 11h, Equipment List Service...............................................................................13 1.1.2.1.3 INT 12h, Low Memory Size Service..........................................................................13 1.1.2.1.4 INT 13h, Disk Services .............................................................................................14 1.1.2.1.5 INT 14h, Serial Port Services ....................................................................................16 1.1.2.1.6 INT 15h, General System Services.............................................................................17 1.1.2.1.7 INT 16h, Keyboard Services......................................................................................18 1.1.2.1.8 INT 17h, Parallel Port Services..................................................................................19 1.1.2.1.9 INT 18h, Boot Fault Routine .....................................................................................19 1.1.2.1.10 INT 19h, Bootstrap Routine.....................................................................................19 1.1.2.1.11 INT 1ah, Time/Date Services...................................................................................20 1.1.2.2 Table Pointers..................................................................................................................21 1.1.2.2.1 INT 1dh, Video Parameter Table (VPT).....................................................................21 1.1.2.2.2 INT 1eh, Floppy Diskette Parameter Table (DPT)......................................................21 1.1.2.2.3 INT 1fh, Video Graphics Character Table (VGCT)....................................................22 1.1.2.2.4 INT 41h/46h, Fixed Disk Paramter Tables (FDPTs) ..................................................22 1.1.2.3 BIOS Upcalls...................................................................................................................23 1.1.2.3.1 INT 15h Device Management ....................................................................................23 1.1.2.3.1.1 INT 15h Function 4fh..........................................................................................23 1.1.2.3.1.2 INT 15h Function 90h.........................................................................................24 1.1.2.3.1.3 INT 15h Function 91h.........................................................................................24 1.1.2.3.1.4 INT 15h Function 85h.........................................................................................24 1.1.2.3.2 INT 1bh Control-Break Signal...................................................................................25 1.1.2.3.3 INT 1ch User Timer Interrupt....................................................................................25 1.1.2.3.4 INT 4ah Real Time Software Interrupt.......................................................................25 1.1.2.4 CPU Traps/Faults............................................................................................................26 1.1.2.5 Hardware Interrupts.........................................................................................................27 1.10.3 SYSTEM CONFIGURATION TABLE .........................................................................................28 1.11 CONSOLE I/O REDIRECTION ....................................................................................................28 General Software EMBEDDED BIOS User’s Manual ii EMBEDDED BIOS User’s Manual Contents 1.11.1 VIDEO (INT 10H) REDIRECTION ...........................................................................................28 1.11.2 KEYBOARD (INT 16H) REDIRECTION....................................................................................29 1.12 INTEGRATED BIOS DEBUGGER................................................................................................29 1.18 PROTECTED MODE SUPPORT ...................................................................................................30 THE INTEGRATED BIOS DEBUGGER.......................................................................................... 33 2.1 HOW TO USE THE DEBUGGER ....................................................................................................33 2.2 DEBUGGER COMMAND SYNTAX.................................................................................................34 2.2.1 OPERAND TYPES ....................................................................................................................34 2.2.2 EXPRESSIONS .........................................................................................................................34 2.2.3 ADDRESSES............................................................................................................................35 2.3 COMMAND REFERENCE..............................................................................................................36 2.3.1 ? COMMAND ..........................................................................................................................36 2.3.2 + COMMAND..........................................................................................................................36 2.3.3 - COMMAND...........................................................................................................................37 2.3.4 BC COMMAND.......................................................................................................................37 2.3.5 BIOSDATA COMMAND.........................................................................................................37 2.3.6 BL COMMAND .......................................................................................................................38 2.3.7 BP COMMAND .......................................................................................................................38 2.3.8 CIS COMMAND ......................................................................................................................39 2.3.9 CONSOLE COMMAND ..........................................................................................................39 2.3.10 CSR COMMAND...................................................................................................................40 2.3.11 CSW COMMAND..................................................................................................................40 2.3.12 D COMMAND .......................................................................................................................41 2.3.13 DA20 COMMAND.................................................................................................................41 2.3.14 DB COMMAND.....................................................................................................................42 2.3.15 DCACHE COMMAND ..........................................................................................................42 2.3.16 DD COMMAND.....................................................................................................................42 2.3.17 DW COMMAND....................................................................................................................43