release

来自「坦尼保姆」· 代码 · 共 34 行

	IMPLEMENTATION ISSUES AND PROBLEMS

The assembler requires that the sections are defined in the order 
TEXT, DATA, BSS. After the first occurrences, the remaining section
directives can appear in any order. 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 right order.
It also supplies the initial labels "TxtSectHd" and "DaSecHd",
so all the requirements are automatically met if it is included in
the first line of the (first) source file.

It is necessary that the names of labels, variables and constants
are unique over all source files. The 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.

There are several known bugs as follows:

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.

Our intention is to correct the problems with the segment
registers in forthcoming versions.