At present it does not support floating point operations.
(All EM floating point instructions are translated to the
68000 "trap" instruction.)
-The m68k2 back end generates code for the ACK 68000 assembler/linker.
+The m68k2 back end generates code for the ACK 68000 assembler.
(The mnemonics recognized by this assembler can be found in
-"as/mach3.c"). As this assembler/linker does not define an
-object (.o) format, it can only link assembly files. Consequently,
-all library modules are stored as assembly files.
+"as/mach3.c").
Some parts of the back end are system dependent, i.e. they depend
on the kind of target 68000 system.
problem. E.g. UniSoft Unix requires a "tst.b N(sp)" instruction
This instruction is generated by the routines "prolog()" and
"save" in "cg/mach.c".
- - The output of the ACK 68000 assembler/linker is an a.out file that
+ - The output of the ACK 68000 linker is an a.out file that
has a different format as an a.out file on your system. (As most
68000 systems have different a.out formats, there is no such thing
as "the" 68000 a.out format). So a program is needed to convert the
- ACK a.out format (i.e. a series of "emitrecs" as defined in
- "as/frame.c") to your a.out format (as defined in
- "/usr/include/a.out.h"). The 1-page program "dl/cv.c" does
+ ACK a.out format to your a.out format (as defined in
+ "/usr/include/a.out.h"). The program "cv/cv.c" does
the job for UniSoft Unix. It probably need only be slightly
modified for your system. Note that the program
generates no text or bss segments, but only a data segment.
68000, you will need a program to download the ACK a.out file.
The program "dl/dl.c" produces Intel Hex format on standard output
from an a.out file.
- - The EM runtime start-off ("libem/head_em.s") may have to be modified.
+ - The EM runtime start-off ("libsys/head_em.s") may have to be modified.
It should call the procedure _m_a_i_n with parameters (argc,argv,envp).
Usually, Unix will put these on top of the stack before starting
the program. Note, however, that for 4-byte systems Unix will provide
a 4-byte argc, while _m_a_i_n expects a 2-byte argc; so the value
must be shortened to 2 bytes.
- The head_em also does a brk() system call to allocate the bss.
- (The size of the bss cannot be obtained from an ACK a.out file).
The m68k2 code generator translates most EM instructions in line.