[f-cpu] fctools 0.3 uploaded to seul.org

[Michael Riepe <michael@stud.uni-hannover.de>]

Hi F-gang!

I uploaded fctools-0.3.tar.gz to http://f-cpu.seul.org/~f-cpu/new/.
Highlights of this release:

*   I finished the linker.  It supports only static binaries and
    relocatable objects (that is, no shared libraries), but that
    should be sufficient for the moment.

*   There also is a second emulator, called `elfemu'.  It emulates
    a basic Unix/Linux operating system running on an F-CPU,
    including virtual memory and a reasonable set of system calls.
    Currently, it runs only static binaries, but that's all you can
    build with the most recent tools anyway.  See the README file
    for a description how to build ELF binaries, and how to run them.

*   (fcpu-)as accepts a new option `-T <hexval>' which sets the load
    address of a binary created with `-O bin'.  The machine emulator
    `emu' still loads a binary at address 0, though.

*   (fcpu-)emu now uses a table-based instruction decoder that
    should be faster than the compare-and-jump tree gcc generated
    for the `switch' statement I used before.  Gcc compiles `emu.c'
    a little faster now, and needs less memory.

*   The `bitrev' instruction now right-shifts by the number of bits
    indicated by the third operand (as the manual states it).
    I also changed EU_SHL to match the emulator (not released yet).

*   I changed the system calling conventions.  In release 0.2, you had
    to execute

        move first_arg, r1
        move second_arg, r2
        ...
        syscall $syscall_number, r0
        move r1, result

    but that's suboptimal.  In 0.3, the sequence has changed to

        move first_arg, r2
        move second_arg, r3
        ...
        loadconsx $syscall_number, r1
        syscall $0, r0
        move r1, result

    which allows us to define a single assembler function that accepts
    the syscall number as an argument (which was impossible before):

            .text
            .p2align 5
            .globl _syscall
        _syscall:
            syscall $0, r0
            // handle return values (-4096...-1 means there was an error)
            loadconsx.0 $-4097, r2
            cmple.64 r2, r1, r3
            loadcons $errno, r2
            jmpl r3, r63        // not an error, return result
            store.32 r2, r1     // store code in `errno' and return -1
            loadconsx.0 $-1, r1
            jmp r63

            .comm errno,4,4

    Now we can write something like

        #include <unistd.h>

        /* this should go into a header file */
        #define SYS_read 1
        #define SYS_write 2
        extern long _syscall(unsigned long, ...);

        ssize_t
        read(int fd, void *buf, size_t len) {
            return _syscall(SYS_read, fd, buf, len);
        }

        ssize_t
        write(int fd, const void *buf, size_t len) {
            return _syscall(SYS_write, fd, buf, len);
        }

    to create system call wrappers in C.  I also added a lot of system
    calls, but only to `elfemu' (see emu/syscalls.def for a list
    of supported functions).  `emu' still accepts only `exit' (0),
    `read' (1) and `write' (2) - and I guess it will stay that way.

*   A number of bugs has been fixed.

Have fun,
-- 
 Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
 "All I wanna do is have a little fun before I die"
*************************************************************
To unsubscribe, send an e-mail to majordomo@seul.org with
unsubscribe f-cpu       in the body. http://f-cpu.seul.org/