E-MMI software: input/output functions

E-MMI software

Input/output functions

To make input/output procedures in E-MMI easier, I offer alternative way of system calls organization. There's a Russian saying "to invent a bicycle", that means trying to do what had been already done many years ago. So I tried not to invent myself this thing again and took CP/M structure of console calls (see this link for example) as a base.

To initiate any input/output procedure in E-MMI you can write instruction 00 05 <N> <reg> (TRAP 05 <N> <reg>), where N is a number of function and reg is a register for input /output information.

Function 01: CONSOLE INPUT

Actions: Input symbol from keyboard into specified register

Details: wait, if symbol is not ready; automatically print symbol on display; try to terminate program, when "CTRL"+"C" combination is pressed

Example:
00 05 01 07 TRAP 05/01 $07 get symbol from keyboard to $7

Function 02: CONSOLE OUTPUT

Actions: print symbol from specified register

Example:
E3 03 0031 SETL $03, 31 put code of symbol '1' into $3
00 05 02 03 TRAP 05/02 $03 print symbol from $3 on display

Function 06: DIRECT CONSOLE

Actions: Input symbol from keyboard into specified register or print it

Details:

if input register = FFh, read keyboard: register is set to 0 if symbol is not ready and equal to symbol code otherwise; ignores "CTRL"+"C" combination
Example:
E3 03 00FF SETL $03, FF set $3 equal to FF
00 05 06 03 TRAP 05/06 $03 get symbol from keyboard to $3 if ready
if specified register is not equal to FFh, print symbol from it
Example:
E3 03 0031 SETL $03, 31 put code of symbol '1' into $3
00 05 06 03 TRAP 05/06 $03 print symbol from $3 on display

Function 09: STRING OUTPUT

Actions: Print string till symbol '$'
Ending symbol '$' is a very old tradition, upcoming to CP/M. I'm not sure it is a good idea to follow this custom, but in current E-MMI version it is supported

Details: E-MMI software cuts the string if it is longer than 250 symbols

Example:
E3 00 00E1 SETL $00, E1 address of string buffer to $0
00 05 09 00 TRAP 05/09 $00 print string

Function 0A: BUFFERED INPUT

Actions: input text string till "Enter"

Details: Specified register before function call must show to free memory area and its first byte is set to maximum string length. After its work, function returns the following information: the number of entered symbols (CR symbol is not included into this number!) in the second byte of buffer; then input string is placed (code CR is presented).

Example: will be published later

Function 0B: CONSOLE STATUS

Actions: returns 0 to specified register if keyboard symbol is not ready and FFh otherwise

Example:
00 05 0B 07 TRAP 05/0B $07 get keyboard status to $7

Function 0C: GET VERSION

Actions: print date of I/O functions release

Example:
00 05 0C 00 TRAP 05/0C $00

Current Pascal source for I/O functions module is also published on my site. I hope it may help somebody to understand the details of I/O in E-MMI.

Please note that not all functions are tested carefully. For example, function 0A is practically a draft.

Related topics:

E-MMI software