From: nowhere@nospicedham.nevernet.at   
      
   On 26/12/2022 12:08, Jean pierneef wrote:   
   > On Monday, December 26, 2022 at 11:33:44 AM UTC+2, Jean pierneef wrote:   
   >> For the purpose of getting to grips with debug.exe on MSDOS 6.22 I have the   
   following code example:   
   >>   
   >> .model tiny   
   >> .data   
   >> msg DB 'test string',0   
   >> .code   
   >> start:   
   >> mov al,msg   
   >> end start   
   >>   
   >> When I compile it with tasm /zi t.asm and link it with tlink t I get the   
   following behaviour in debug.exe:   
   >>   
   >> When pressing 'r' to show registers and next command, I get:   
   >>   
   >> mov al,[0008] as the next instruction to execute.   
   >>   
   >> I was expecting the memory location of 'test string' to thus be at ds:0008   
   but when I do:   
   >>   
   >> d ds:0108   
   >>   
   >> I find 'test string' there instead (and garbage at ds:0008).   
   >>   
   >> Can somebody please explain why 0100h is 'subtracted' from 0108h when I do   
   the 'r' command in debug.exe ?   
   >   
   > I have tried this on an MSDOS 6.22 running in Virtual Box (tasm v2.0,   
   unknown debug.exe version) as well as on Doxbox (tasm 2.51, debug.exe 1.25   
   which I presume comes from some open source project).   
   >   
   > I do not understand why "test string" is at location ds:0108h in memory, but   
   why debug says it wants to mov 0008 into the al register. Why the discrepancy ?   
      
   MOV AL,msg   ;loads the low byte of the ADDRESS 0108 into AL   
   MOV AL,[msg] ;loads the content of this address   
      
   I don't know Tasm, it may need a keyword (ptr?) instead of brackets   
   __   
   wolfgang   
      
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