HP-41 RAMBox Questions

[Raymond Del Tondo]

(02-18-2020 03:53 AM)Sylvain Cote Wrote:  Included in the manual

• PG01 map RAMBOX #0 even pages (8, 10, 12, 14) and RAMBOX #1 odd pages (9, 11, 13, 15)
• PG10 map RAMBOX #1 even pages (8, 10, 12, 14) and RAMBOX #0 odd pages (9, 11, 13, 15)
• PG<> switches between PG01 and PG10 settings
  

A small correction to your description of PG<> :
According to the manual PG<> switches between RAMBOX 0 and RAMBOX 1,
so if page 8 contains RBOS-"a", all pages are switched to the "b" after issuing PG<> ,
regardless whether banks were interleaved before or not.

(02-18-2020 03:53 AM)Sylvain Cote Wrote:  Missing from the manual (educated guess)

• PG00 map RAMBOX #0 even pages (8, 10, 12, 14) and RAMBOX #0 odd pages (9, 11, 13, 15)
• PG11 map RAMBOX #1 even pages (8, 10, 12, 14) and RAMBOX #1 odd pages (9, 11, 13, 15)
  

Not needed, since PG<> completely switches to RAM Box 0 or 1.

This is what I noted back then when analyzing the CY OS:

Code:


*        ENBANK functionality in the RAMBOX:
*        --------------------------------------
*        ENBANK1: reset all pages to bank A
*        ENBANK2: enable odd pages of bank B
*        ENBANK3: enable even pages of bank B
*****************************************************************************
    .NAME    "PG<>"

***Bank A
[8DBC]    ENROM2
        ENROM3

***Bank B
*[8DBC]    C=0    ALL
*        ENROM1

        RTN

*****************************************************************************
    .NAME    "PG01"
[8DC3]    ENROM1                    ; Reset all pages to bank A
        ENROM2                    ; enable odd pages of bank B
        RTN

*****************************************************************************
    .NAME    "PG10"
[8DCA]    ENROM1                    ; Reset all pages to bank A
        ENROM3                    ; enable even pages of bank B
        RTN