User`s guide

ROM Partitioning

B.1 Firmware EPROM Layout

A descriptor of the input string is returned in R0 and R1. R0 contains the

length of the string and R1 contains the address. This routine inputs the

string into the console program string buffer and therefore the caller need not

provide an input buffer. Successive calls however destroy the previous contents

of the input buffer.

Registers R0 and R1 are modiﬁed by this routine, all others are preserved.

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

; Usage with a message descriptor (position independent).

pushab 5$ ; Generate prompt desc.

pushl #10$-5$ ; on stack.

movl sp,r0 ; Pass desc. addr. in R0.

clrl r1 ; Specify no time-out.

jsb @#CP$READ_WTH_PRMPT_R4 ; Call routine.

clrq (sp)+ ; Purge prompt desc.

. ; Input desc in R0 and R1.

5$: .ascii /Prompt> / ; Prompt string.

10$:

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

B.1.3 Boot Information Pointers

Two longwords located in FEPROM are used as pointers to the default boot

device descriptor and the default boot ﬂags (Figure B–4), because the actual

location of this data may change in successive versions of the ﬁrmware. Any

software that uses these pointers should reference them at the addresses in

halt-protected space.

ROM Partitioning B–7