Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
PRINT AT 23,0 and FOR NEXT Loop not working after Fastcall
Luzie Wrote:OK.

I´ll paste the called FASTCALL down under.

I´ve tried to save IX register by a PUSH IX and restore it with POP IX, but this changed nothing,

The problem seems to me the TR-DOS-ROM (=Spectrum Betadisk-System) Routine
which is called with the FASTCALL.

But I cannot imagine yet, why this can bring your ZX Basic "out of running correct".

Here´s my used FASTCALL:
FUNCTION FASTCALL MCodeDIRDOSv4 (number as uByte) as uInteger


;BDUC-Newsletter No.5 Page 5 Brothaers TR-DOS v4.XX Example for CAT to SCREEN
CALL 15366                        ;TR-DOS v4 #3C06 = 15366 dez = DOS ON
PUSH HL                            ;Put the DOS OFF return adress on the stack - Needed by TR-DOS v4
LD A,2                            ;Select Stream 2 (screen)
LD C,7                            ;Set DOS Routine 7 (catalogue)
CALL 15357                        ;Call TR-DOS v4 Central Functions adress #3BFD = 15357 dez
RET                                        ;This one jumps to the adress PUSHed with PUSH HL, put DOS Off and returns

You have to save both the SP (stack) and the IX register. FASTCALL is faster and does nothing of this, it's just a pure ASM code (the ubyte parameter is passed in the A register).
I haven't examined what TR-DOS do. Also, ZX BASIC uses the classic 48k ROM variables (i.e.236XX addresses). It might also be that.
Where can I find the TR-DOS asm listings? maybe I can have a look.

Messages In This Thread

Forum Jump:

Users browsing this thread: 1 Guest(s)