Topic       : TOS - The Operating System
Author      : 
Version     : tos.hyp (December 19, 2008)
Subject     : Programmieren/Atari
Nodes       : 3010
Index Size  : 93790
HCP-Version : 5
Compiled on : Atari
@charset    : atarist
@lang       : 
@default    : Title
@help       : 
@options    : +g -i -s +x +zz -t4
@width      : 70
View Ref-File5.1  About the GEMDOS                                              TOS

The GEMDOS is, apart from the hardware-dependent BIOS and XBIOS, the 
actual operating system of the Atari and its functions form the 
highest level of TOS. The functions are called via the 680X0 Trap #1. 
The operating system functions can be easily divided into categories 
by the first letter of the function name:

 ∙ File functions           (F...)
 ∙ Date and Time            (T...)
 ∙ Process functions        (P...)
 ∙ Memory management        (M...)
 ∙ System functions         (S...)
 ∙ Directory functions      (D...)
 ∙ Character input/output   (C...)

Under MagiC, GEMDOS is reentrant (as of MagiC 3.0 this applies even 
for the file-system!). This is visible, for instance, by alert boxes 
of the type "Data in Drive A: may be damaged" being movable - because 
memory has to be demanded for this, which does not work under 
(Multi)TOS, as a file operation in GEMDOS is being handled at the same 
time.

With the appearance of MiNT, the GEMDOS was extended by many 
functions. Also MagiC as of Version 3.0 possesses some MiNT-compatible 
functions and MetaDOS drivers with corresponding functionality have 
been spotted.

The GEMDOS receives its parameters on the stack; for this, the last 
argument from the parameter list is stored as the first on the stack. 
Function results are returned in processor register d0. Only the 
registers d3-d7 and a3-a7 are saved, all others will be altered by the 
call.

See Also: XFS-concept in MagiC   Background-DMA   Program format 
Function list