Arche Legacy BIOS Post Codes:

Derives from AMI BIOS and uses port 80h.   Certain codes come up if a copy is made without AMI's copyright notice.

 01   Disable the NMI and test CPU registers 
 02   Verify the BIOS ROM checksum (32KB at F8000h) 
 03   Initialize the keyboard controller and CMOS RAM communication 
 04   Disable the DMA and PIT; test the CMOS RAM interrupt 
 05   Reset the video controller 
 06   Test the 8254 programmable interrupt timer 
 07   Test delta count timer channel 2 (speaker) 
 08   Test delta count timer channel 1 (memory refresh) 
 09   Test delta count timer channel 0 (system timer) 
 0A   Test parity circuit and turn on refresh 
 0B   Enable parity check and test system timer 
 0C   Test refresh trace link toggle 
 0D   Test refresh timing synchronization 
 10   Disable cache and shadow memory; test the 64KB base memory 
 11   Perform 64KB memory read/write test 
 12   Initialize interrupt vector table in lower 1KB of RAM 
 14   Test CMOS RAM shutdown register...disable DMA and interrupt controllers 
 15   Test CMOS RAM battery and checksum 
 16   Test for floppy drive, based on CMOS setup...initialize monochrome video 
 17   Initialize CGA video 
 18   Clear the parity status (if any) 
 19   Test for EGA/VGA video BIOS at C0000h and pass control 
 1A   Return from video ROM 
 1B   Test primary video adapter...test video memory 
 1C   Test secondary video adapter...test video memory 
 1D   Compare CMOS settings to video adapter 
 1E   Set video mode according to CMOS settings 
 20   Display CMOS RAM read/write errors and halt 
 21   Set cursor and call interrupt 10 to display status message 
 22   Display power on message; "386 BIOS"; check if CPU speed is 25Mhz or 33Mhz 
 23   Read new cursor position 
 24   Display AMI copyright message at the bottom of the screen 
 25   Test shadow RAM 
 F0   Shadow RAM test failed 
 30   Ready to enter protected mode 
 31   Enter protected mode (A20 gate) and enable timer interrupt (IRQ 0) 
 32   Get memory size above 1MB 
 33   Get memory size below 640KB 
 34   Test memory above 1MB 
 35   Test memory below 1MB 
 37   Clear memory below 1MB 
 38   Clear memory above 1MB 
 39   Use CMOS shutdown byte and return to real mode 
 3A   Test 64KB read/write 
 3B   Test RAM below 1MB and show the area being tested 
 3C   Test RAM above 1MB and show the area being tested 
 3D   RAM test complete OK 
 3E   Ready to return to real mode 
 3F   Back in real mode 
 40   Disable A20 gate 
 41   Check for AMI copyright message in ROM 
 42   Display the AMI copyright message, if found 
 43   Test cache memory; Clear <Esc> message 
 4E   Process shutdown 1; Return to real mode 
 4F   Restore interrupt vectors and data in BIOS RAM area 
 50   Test DMA controller 
 51   Initialize DMA controller 
 52   Test the DMA controller with patterns 
 54   Test DMA controller latches 
 55   Initialize and enable DMA controllers 1 and 2 
 56   Initialize 8259 programmable interrupt controllers 
 57   Test 8259 programmable interrupt controllers and setup interrupt mask registers 
 61   Check DDNIL status bit and display message 
 70   Perform keyboard (BAT) basic assurance test 
 71   Program keyboard to AT type 
 72   Disable keyboard and initialize keyboard circular buffer 
 73   Display message and initialize floppy controller and drive 
 74   Attempt to access the floppy drive 
 75   If the CMOS RAM is good, check and initialize the hard disk controller and drive 
 76   Attempt to access the hard disk drive 
 77   Shuffle and internal error codes 
 79   Check CMOS RAM battery and checksum...clear parity status 
 7A   Compare size of base/extended memory to CMOS information 
 7B   Unknown AMI function 
 7C   Display AMI copyright 
 7D   Set AT memory expansion bit 
 7E   Verify the ROM contains and AMI copyright 
 7F   Clear the <Del> message from the display...check if <Del> was pressed 
 80   Locate option ROM at C800h to DE00h and pass control to any found 
 81   Return from option ROM and initialize timer and data area 
 82   Setup parallel and serial ports 
 83   Test for math coprocessor 
 84   Check if keyboard is locked 
 85   Display any soft error messages 
 86   Test for option ROM at E0000h 
 A0   Error found in 256KB or 1MB RAM IC in lower 640KB 
 A1   Base 64KB random access and data pattern test (only in 386APR and Presto 386SX BIOS) 
 A9   Initialize on board VGA controller (Presto 386SX BIOS) 
 B0   Error in 256KB RAM IC in 640KB 
 B1   Base 64KB random access and data pattern test (only in Presto 386SX BIOS) 
 E0   Return to real mode and initialize base 64KB RAM (Presto) 
 E1   Initialize 640KB RAM (Presto) 
 EF   Configuration memory error - can't find memory 
 F0   Test shadow RAM from 04000h 
 00   Call the interrupt 19 boot loader