Here is a nice TXT that explains interrupt vector assignments, and more differences between the 'A' and 'B' models (and DOS 2.01 vs. 2.05).

I was asked about IRQ priorities. VBI has highest,
'Interrupt from Z80' has lowest priority (others are in between, in the order shown below for 40 thru 47 or A0 - A7
.

Subj: MS-DOS Interrupt Vector Assignment

Rainbow 100 MS-DOS Interrupt Vector Assignment (in hexdecimal)

Interrupt 0 - Divide by zero
Interrupt 1 - Single step
Interrupt 2 - NMI used for Memory Parity error or 8087 error
Interrupt 3 - Break point instruction
Interrupt 4 - Overflow

Interrupt 18 - Firmware functions

Interrupt 20 - DOS program terminate
Interrupt 21 - DOS function call
Interrupt 22 - DOS terminate address
Interrupt 23 - DOS Control-Break exit address
Interrupt 24 - DOS fatal error address
Interrupt 25 - DOS absolute disk read
Interrupt 26 - DOS absolute disk write
Interrupt 27 - DOS terminate & fix in storage
Interrupt 28 thru 3F - Reserved for DOS

; INT 40 thru 47 are used for hardware interrupt if:
; 1. use MS-DOS V2.01,
; 2. use RAINBOW 100 (not 100+).

Interrupt 40 - Vertical frequency refresh interrupt
Interrupt 41 - Not used
Interrupt 42 - Graphic controller interrupt
Interrupt 43 - DMA controller interrupt (from extended comm. board)
Interrupt 44 - Communication/Printer interrupt
Interrupt 45 - Hard disk or Extended communication interrupt
Interrupt 46 - Keyboard interrupt
Interrupt 47 - Interrupt from Z80

Interrupt 64 - timer (60 or 50 ticks/second)

; INT A0 thru A7 are used for hardware interrupt if:
; use MS-DOS V2.05 (or above) WITH RAINBOW 100+.

Interrupt A0 - Vertical frequency refresh interrupt
Interrupt A1 - Not used
Interrupt A2 - Graphic controller interrupt
Interrupt A3 - DMA controller interrupt (from extended comm. board)
Interrupt A4 - Communication/Printer interrupt
Interrupt A5 - Hard disk or Extended communication interrupt
Interrupt A6 - Keyboard interrupt
Interrupt A7 - Interrupt from Z80

Interrupt F0 - Alternate DOS interrupt 22 - Terminate address
Interrupt F1 - Alternate DOS interrupt 23 - Control-Break exit address
Interrupt F2 - Alternate DOS interrupt 24 - Fatal error address

3. alternate interrupt vectors for DOS INT 20-27

DOS INT 20 ------------> INT F8
DOS INT 21 ------------> INT F9
DOS INT 22 ------------> INT F0
DOS INT 23 ------------> INT F1
DOS INT 24 ------------> INT F2
DOS INT 25 ------------> INT FD
DOS INT 26 ------------> INT FE
DOS INT 27 ------------> INT FF

if you read it by interrupt vectors order:

INT F0 ---- DOS INT 22
INT F1 ---- DOS INT 23
INT F2 ---- DOS INT 24
INT F3 thru F7 reserved by DOS
INT F8 ---- DOS INT 20
INT F9 ---- DOS INT 21
INT FA ---- reserved by BIOS
INT FB ---- reserved by BIOS
INT FC ---- reserved by BIOS
INT FD ---- DOS INT 25
INT FE ---- DOS INT 26
INT FF ---- DOS INT 27

Source: RBTECDOC.ZIP (Latrobe and mirrors)


Last edited by Bavarese; 03/11/14 03:22 PM.