forum.petersplus.com - Internet forum

I'm going to reference some functions by header files to shorten this message:

assert.h, ctype.h, stdio.h, string.h

Floating point routines, exit, atexit, malloc, free etc

Console stdio is supported. I've implemented file routines, but not fully tested them - I understand that there's a problem with directories on the real hardware - but through SPRINT reading files certainly works.

Graphics isn't supported at all - I've not had time to read through the available source code and docs to implement it.

z88dk supports the concept of far pointers, so in theory far data can be read, however far data support is built upon machine specific libraries which hasn't been implemented for the Sprinter.

Far code is problematic and is something that hasn't been implemented yet, it would certainly be possible to write a wrapper function that takes a far pointer and then calls the function. However, the destination function would have to be in a separately compiled program and you might as well incorporate dll (libman) support into the port. Unfortunately, the assembler used doesn't support the concept of overlays/segments which would make implementing native far code somewhat tricky.

Thoughts have been appearing about replacing the assembler with something like asz80 but at present they're just thoughts and nothing has been done.

Color attribute:

bit7 - blink
bit6,5,4 - background (0...7) RGB
bit3,2,1,0 - foreground (0..15) IRGB

0 Black
1 Blue
2 Green
3 Cyan
4 Red
5 Magenta
6 Brown
7 White
8 Gray
9 Bright blue
10 Bright green
11 Bright cyan
12 Bright red
13 Bright magenta
14 Yellow
15 Bright white

;this don't working on the Sprinter, but working in emulator.
LD IX,something
LD HL,something
LD B,something
LOOP LD A,(HL)
INC HL
LD C,DSS_FUNCTION
RST #10
DJNZ LOOP
LD A,(IX)

;this will work both on the Sprinter and in the emulator.
LD IX,something
PUSH IX
LD HL,something
LD B,something
LOOP LD A,(HL)
INC HL
PUSH HL
PUSH BC
LD C,DSS_FUNCTION
RST #10
POP BC
POP HL
DJNZ LOOP
POP IX
LD A,(IX)

Start applications:

The programs stored on the disk in binary executable files.
One of main task for operating system, it's start the programs.
The command line for program has following format:

[device:][\path\]name [parameters]

The device and path specified location on the disk. If they are missed.
Then program searching in current directory.
EXE files contain, special prefix and program code.

EXE-file prefix:

+00 2 dw 5845h ; EXE signature
+02 1 db 45h ; Reserved (exe type)
+03 1 db 00h ; Version of EXE-format
+04 4 dd 00000200h ; Begin of program code (bytes offset)
+08 2 dw 0000h ; Size of primary loader or 0
+10 4 dd 00000000h ; Reserved
+14 2 dw 0000h ; Reserved
+16 2 dw ???? ; Load address
+18 2 dw ???? ; Start addres (register PC)
+20 2 dw ???? ; Stack addess (register SP)
+22 490 ds 0 ; Reserved

+512 ; Code of program

40h (64) EXEC (Execute EXE-file)

input:

HL - file specification
B = 0 - load and execute program
C - 40h

output:

A - exit code, if CF=0
error, if CF=1

The following steps used for start a program:

1) Opens exe-file for read;
2) Reads exe-prefix to working buffer;
3) Allocates memory required for loading this file or primary loader,
if size of primary loader != 0;
4) Save STACK
5) Pages allocated memory;
6) Builds Program start prefix and point IX to it;
7) Reading file to the address that specified in field 16 (Load address);
8) Closes exe-file, if it not a primary loader;
9) Sets STACK at value specified in field 20 (Stack address);
10) Jump to program code that specified in field 18 (Start address);

Program start prefix:

-03 1 db ? ; File handle, if exe-file has primary loader
-02 1 db ? ; Memory handle for this exe-file
-01 1 db ? ; Level of current program
+00 1 db ? ; Length of command line parameters
+01 127 ds ? ; Parameters of command line with null-terminated

Example:
LD HL,NAME ;HL point to ASCIIZ string with filename
LD C,40h ;Exec fn.
LD B,00h ;Subfn. load and execute
RST 10h ;Call DSS
RET C ;Return if Error
LD (ENDCODE),A ;Save exit code

NAME DB "\PROG\UTILITY\prog.exe",0
ENDCODE DB 00h