[<<Previous Entry]
[^^Up^^]
[Next Entry>>]
[Menu]
[About The Guide]
Int 4A - Acorn Bbc Master 512 - "osword" - Misc Functions Using Control [O]
AL = function code
FAh transfer data between 80186 and 65C12 I/O processor
DS:BX -> control block (see below)
Return: FLAGS destroyed
control block updated
Note: there are more functions than are listed here, but details are not
available
See Also: INT 40"Acorn",INT 4B"Acorn",INT 4C"Acorn"
Format of control block for function FAh:
Offset Size Description
00h BYTE number of parameters sent to I/O processor (0Dh,0Eh)
01h BYTE number of parameters read from I/O processor (01h)
02h DWORD I/O processor address
06h DWORD 80186 segment:offset address
0Ah WORD number of bytes to transfer
0Ch BYTE operation type
00h write to 65C12 at 24 us/byte
01h read from 65C12 at 24 us/byte
02h write to 65C12 at 26 us/word
03h read from 65C12 at 26 us/word
04h write to 65C12 at 10 us/byte using 256-byte blocks
05h read from 65C12 at 10 us/byte using 256-byte blocks
0Dh BYTE 65C12 memory access control (only used if offset 00h = 0Eh)
bit 7: unused
bit 6: always use main screen memory if I/O addr 3000h-7FFFh
(overrides bit 5)
bit 5: use shadow screen memory if screen address specified
bit 4: use current ROM rather than ROM selected by bits 3-0
(only if I/O address between 8000h and BFFFh)
bits 3-0: paged ROM number
This page created by ng2html v1.05, the Norton guide to HTML conversion utility.
Written by Dave Pearson