User`s guide

ROM Partitioning

B.1 Firmware EPROM Layout

All of the entry points are designed to run at IPL 31 on the interrupt stack

in physcial mode. Virtual mode is not supported. Due to internal ﬁrmware

architectural restrictions, users are encouraged to only call into the halt-

protected entry points. These entry points are listed in Table B–3.

Table B–3 Call-Back Entry Points

CP$GET_CHAR_R4 20040008

CP$MSG_OUT_NOLF_R4 2004000C

CP$READ_WTH_

PRMPT_R4

20040010

B.1.2.1 CP$GETCHAR_R4

This routine returns the next character entered by the operator in R0. A

timeout interval can be speciﬁed. If the timeout interval is zero, no timeout is

generated. If a timeout is speciﬁed and if timeout occurs, a value of 18 (CAN)

is returned instead of normal input.

Registers R0,R1,R2,R3 and R4 are modiﬁed by this routine, all others are

preserved.

;---------------------------------------------------------------

; Usage with timeout:

movl #timeout_in_tenths_of_second,r0 ; Specify timeout.

jsb @#CP$GET_CHAR_R4 ; Call routine.

cmpb r0,#^x18 ; Check for timeout.

beql timeout_handler ; Branch if timeout.

; Input is in R0.

;---------------------------------------------------------------

; Usage without timeout:

clrl r0 ; Specify no timeout.

jsb @#CP$GET_CHAR_R4 ; Call routine.

; Input is in R0.

;---------------------------------------------------------------

ROM Partitioning B–5