inital SS:SP value in MZ

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vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 27 Feb 2006, 11:09

what is SS:SP value, when no stack is reserved in header (no "stack 100h")?

27 Feb 2006, 11:09

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8263
Location: Kraków, Poland

Tomasz Grysztar 27 Feb 2006, 13:38

From section 2.4.1:

Quote:

"stack" directive sets up the stack for MZ executable. It can be followed by numerical expression specifying the size of stack to be created automatically or by the far address of initial stack frame when you want to set up the stack manually. When no stack is defined, the stack of default size 4096 bytes will be created.

27 Feb 2006, 13:38

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 28 Feb 2006, 00:36

oh... and what happens at "stack 0"? is ss:sp just pointer to some invalid area?

28 Feb 2006, 00:36

Filter

Joined: 08 Oct 2006
Posts: 67

Filter 26 Oct 2006, 01:15

vid wrote:

oh... and what happens at "stack 0"? is ss:sp just pointer to some invalid area?

Don't EXE files require a stack of some sort? Maybe "stack 0" provides enough for it.

26 Oct 2006, 01:15

Goplat

Joined: 15 Sep 2006
Posts: 181

Goplat 26 Oct 2006, 01:42

fasm does not allow "stack 0", but if you put a 0 in the SP field of the header the stack pointer does indeed start at 0. Of course, it would wrap around when you used it, and if not enough extra memory was allocated for a 64kB stack you would be overwriting some stuff in memory.

26 Oct 2006, 01:42

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