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+--- Thread: 41CX's ED: Lower Case & Special Chars patch (/thread-8775.html)
41CX's ED: Lower Case & Special Chars patch - Ángel Martin - 08-04-2017 05:33 AM
41CX: Adding Lower Case & Special Chars to ASCII File Editor.
The standard ASCII file Editor on the 41CX has no support for lower case and other special characters. As a consequence, those chars need to be entered first in ALPHA and then manually transferred to the ASCII file using APPCHR or APPREC; either way the user needs to exit the editor, make the manual transfer, and call ED again.
With this patch entering lower-case and special characters is simply done by typing the designated key from within ED itself, no need for intermediate cumbersome steps.
The special chars keyboard layout is the same one available for ALPHA mode on the OS/X Module (and in turn on the original CCD Module) with USER off. There are two conceptual differences though:
1. Since ED uses the USER key to move the cursor one position to the left, that cannot be the mode flag in this case. Activation of the lower case & special chars is done switching ALPHA off instead.
2. With ALPHA switched off, the "native" ED uses the numeric keys to enter digits , radix and the unary minus sign. That is not changed, and therefore imposes a design for the rest of available choices. This forces an inverted scheme for the layout compared to the OS/X, as follows:
- Special characters are in the same positions as in the OS/X, but accessed using non-Shifted keys. The exception to this rule are the "little men" characters, which use letters [A], [B], [C], and [K] instead.
- Lower-case letters are accessed using SHIFTED keys - from SHIFT-A for "a" thru SHIFT-Z for "z". The only exception being "l" and "m", which use the non-shifted keys "L" and "M" ( as LBL and GTO are reserved for the insertion mode and go-to-record functions within ED).
Easier to use it than to describe it - specially if you have the old CCD overlay at hand. The important thing is that none of the standard features or character layout of the original ED are altered in any way.
Patching the ROM.
All changes are confined within the bank-switched page of the CX-Extended Functions, i.e. ROM_5B. If you use the 41-CL or an emulator capable of altering the OS sector (like V41), then all you have to do is replace said ROM_5B with the new one containing the patch.
Patching instructions. Three steps are necessary:
Step #1. There are only three bytes to change in the original ED code, which is good news since that code is 1,001 bytes long!. The bytes to change are located at 0x5F62, 0x5EF0 and 0x5EF1; where:
0x5F62 has a jump-if-carry to address 5F51 (37F JC - 17d). The jump distance needs to be changed to point at 5F4C instead, i.e.
5F62 357 JC -22d
0x5EF0/F1 has a call to [BLINK] (265 , 020) - this needs to be replaced with a non-conditional jump to address 0x5BF1:
5EF0 3C5 ?NC GO
5EF1 16E ->5BF1
Step #2. Next we need to add the following code at the jumped-to location (which is conveniently empty in the original ROM), to process the key-presses and triage them accordingly:
Code:
5BDF 1B0 POPADR get calling address
5BE0 170 PUSHADR keep it in RTN stack
5BE1 03C RCR 3 move pg# to C<3>
5BE2 0A6 A<>C S&X get absolute TBL adr
5BE3 1BC RCR 11 rotate to ADR field
5BE4 066 A<>B S&X put reference in A[S&X]
5BE5 11A A=C M preserve this address
5BE6 330 FETCH S&X read KEYCODE
5BE7 2E6 ?C#0 S&X value non-zero?
5BE8 14D ?NC GO NO, Skip one line and RTN
5BE9 032 ->0C53 [SKIP1]
5BEA 23A C=C+1 M add offset until
5BEB 366 ?A#C S&X are they different?
5BEC 01B JNC +03 no, exit loop
5BED 23A C=C+1 M next addr field
5BEE 3BB JNC -09 loop back
5BEF 330 FETCH S&X get func. address
5BF0 3E0 RTN and return
5BF1 066 A<>B S&X sought-for value
5BF2 130 LDI S&X beginning of table
5BF3 3F9 CON: [LWRCAS]
5BF4 1F6 C=C+C XS "6F9"
5BF5 106 A=C S&X start of table
5BF6 37D ?NC XQ search ADDR in table
5BF7 16C ->5BDF [SRCHR1]
5BF8 02B JNC +05 [GOTCHA]
5BF9 265 ?NC XQ blink screen
5BFA 020 ->0899 [BLINK]
5BFB 3C9 ?NC GO return to main code
5BFC 17A ->5EF2 [CURSR2]
5BFD 106 A=C S&X replaced char#
5BFE 075 ?NC GO take over from here
5BFF 17A ->5E1D [VALID1]Step #3. The code above relies on a character table that needs to be added to the ROM. We do this in another empty section, not to disturb any existing code - as follows:
Code:
56F9 041 shift-"A"
56FA 061 "a"
56FB 042 shift-"B"
56FC 062 "b"
56FD 043 shift-"C"
56FE 063 "c"
56FF 044 shift-"D"
5700 064 "d"
5701 045 shift-"E"
5702 065 "e"
5703 046 shift-"F"
5704 066 "f"
5705 047 shift-"G"
5706 067 "g"
5707 048 shift-"H "
5708 068 "h"
5709 049 shift-"I "
570A 069 "i"
570B 04A shift-"J "
570C 06A "j"
570D 04B shift-"K"
570E 06B "k"
570F 04C "L"
5710 06C "l"
5711 04D "M"
5712 06D "m"
5713 04E shift-"N"
5714 06E "n"
5715 04F shift-"O"
5716 06F "o"
5717 050 shift-"P"
5718 070 "p"
5719 051 shift-"Q"
571A 071 "q"
571B 052 shift-"7"
571C 072 "r"
571D 053 shift-"8"
571E 073 "s"
571F 054 shift-9"
5720 074 "t"
5721 055 shift-"U"
5722 075 "u"
5723 056 shift-4"
5724 076 "v"
5725 057 shift-"5"
5726 077 "w"
5727 058 shift-"6"
5728 078 "x"
5729 059 shift-"Y"
572A 079 "y"
572B 05A shift-"1"
572C 07A "z"
572D 03D shift-"2"
572E 10C "m"
572F 03F shift-"3"
5730 021 "|"
5731 020 shift-"0"
5732 101 "pi"
5733 064 "D"
5734 05B "["
5735 065 "E"
5736 05D "]"
5737 07E "F"
5738 01F "spat"
5739 025 "G"
573A 040 "@"
573B 01D "H"
573C 023 "#"
573D 03C "I"
573E 028 "("
573F 03E "J"
5740 029 ")"
5741 05E "N"
5742 027 " ' "
5743 024 "P"
5744 022 " " "
5745 02D "-"
5746 05F "_"
5747 02B "+"
5748 026 "&"
5749 02A "*"
574A 060 "t"
574B 02F "/"
574C 05C "\"
574D 02C shift-radix
574E 03B ";"
574F 03F shift-"?"
5750 021 "|"
5751 03A shift-"/"
5752 100 upper "_"
5753 000 <end of table>That's all there's to it folks - enjoy your enhanced ED+ !
PS. With this enhancement it's possible to enter any formula expression used by the Formula Evaluation module directly in an ASCII record. Refer to the following for details: http://www.hpmuseum.org/forum/thread-8622.html?highlight=formula+evaluation
PPS. To *visualize* the lower-case letters in the LCD you need to use a half-nut machine, and also apply the patch provided by JF-Garnier in the following link:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=1205