release.txt

IMPLEMENTATION ISSUES AND PROBLEMS

I. IMPLEMENTATION ISSUES

1.   The assembler requires sections to be defined in the following order: 

     TEXT
     DATA
     BSS

     After the first occurrences, remaining section directives may appear in 
     any order. 

2.   It is advisable to give the 0 addresses in all three sections a global 
     label, so they can be referred to by code and data. The header file 
     "syscalnr.h" defines the system call numbers and the sections in the 
     correct order. It also supplies the initial labels "TxtSectHd" and 
     "DaSecHd". Therefore, all requirements are automatically met if 
     syscalnr.h is included in the first line of the (first) source file.

3.   All label, variable and constant names must be unique across all 
     source files. 

4.   Line numbers mentioned by the assembler in case of errors and warnings 
     are with respect to the ".$" file. This means, for example, that the 
     position of the error in the ".s" file will be 20 lines lower when the 
     file with system call numbers "syscalnr.s" is included in the first line.

II. KNOWN BUGS 

1.   There is a problem in the overflow flag and the carry flag in
     the IMUL.

2.   Far jumps and calls generate segmentation faults and must not
     be used.

3.   In instructions with segment override, the source list pointer
     in the tracer misses one instruction, and in the segment register
     change, the stack window loses track of where it is.