bug-report: egcs-1.1.1 m68k-coff-gcc (coldfire)

[Rolf Fiedler]

Hi there,

this is probably the wrong list to send this bug report to, but I
thought
somebody on this list will know what to do with it.

----------------------------------------------------------
the following piece of code causes egcs gcc to emit illegal coldfire
instructions:

#define IO_BASE 0x10000000
typedef unsigned char BYTE;
/*   page 1, read */
#define RTL_PAR0    (*(volatile unsigned char *)(IO_BASE + 0x00002301))
#define RTL_PAR1    (*(volatile unsigned char *)(IO_BASE + 0x00002302))
#define RTL_PAR2    (*(volatile unsigned char *)(IO_BASE + 0x00002303))
#define RTL_PAR3    (*(volatile unsigned char *)(IO_BASE + 0x00002304))
#define RTL_PAR4    (*(volatile unsigned char *)(IO_BASE + 0x00002305))
#define RTL_PAR5    (*(volatile unsigned char *)(IO_BASE + 0x00002306))
/* Get the actual MAC address out of the Ethernet chip */
long long EthGetMAC(void) {
    long long temp;
    EthSetPage(1);
    temp = RTL_PAR0;
    temp |= (long long)RTL_PAR1 << 8;
    temp |= (long long)RTL_PAR2 << 16;
    temp |= (long long)RTL_PAR3 << 24;
    temp |= (long long)RTL_PAR4 << 32;
    temp |= (long long)RTL_PAR5 << 40;
    return temp;
}

the compilation shows the following results:

rfie@pontifex:/home/rfie > m68k-coff-gcc --version
egcs-2.91.60
rfie@pontifex:/home/rfie > m68k-coff-gcc -m5200 -c -o short.o short.c
/tmp/ccMS4tFx.s: Assembler messages:
/tmp/ccMS4tFx.s:26: Error: invalid instruction for this architecture;
needs 68000 or higher -- statement `rol.l #8,%d3' ignored
/tmp/ccMS4tFx.s:27: Error: invalid instruction for this architecture;
needs 68000 or higher -- statement `rol.l #8,%d2' ignored

rotate is indeed not a valid instruction for coldfires, which is sad.

the assembly output (generated by gcc -S):

.file   "short.c"
gcc2_compiled.:
__gnu_compiled_c:
.text
        .even
.globl EthGetMAC
EthGetMAC:
        link.w %a6,#-8
        lea (-24,%sp),%sp
        movm.l #0xfc,(%sp)
        pea 1.w
        jsr EthSetPage
        addq.l #4,%sp
        move.b 268444417,%d0
        moveq #0,%d6
        moveq #0,%d7
        move.b %d0,%d7
        move.l %d6,-8(%a6)
        move.l %d7,-4(%a6)
        move.b 268444418,%d0
        moveq #0,%d4
        moveq #0,%d5
        move.b %d0,%d5
        move.l %d4,%d2
        move.l %d5,%d3
        rol.l #8,%d3             <- this is ok for 68000, but not for
coldfire
        rol.l #8,%d2
        move.b %d3,%d2
        clr.b %d3
        move.l -8(%a6),%d0
        or.l %d2,%d0
        move.l -4(%a6),%d1
        or.l %d3,%d1
        move.l %d0,-8(%a6)
        move.l %d1,-4(%a6)
        move.b 268444419,%d0
        moveq #0,%d4
        moveq #0,%d5
        move.b %d0,%d5
        move.l %d4,%d2
        move.l %d5,%d3
        swap %d3
        swap %d2
        move.w %d3,%d2
        clr.w %d3
        move.l -8(%a6),%d0
        or.l %d2,%d0
        move.l -4(%a6),%d1
        or.l %d3,%d1
        move.l %d0,-8(%a6)
        move.l %d1,-4(%a6)
        move.b 268444420,%d0
        moveq #0,%d2
        moveq #0,%d3
        move.b %d0,%d3
        move.l %d3,%d4
        lsr.l #8,%d4
        move.l %d2,%d5
        moveq.l #24,%d7
        lsl.l %d7,%d5
        move.l %d4,%d0
        or.l %d5,%d0
        move.l %d3,%d1
        moveq.l #24,%d6
        lsl.l %d6,%d1
        move.l -8(%a6),%d2
        or.l %d0,%d2
        move.l -4(%a6),%d3
        or.l %d1,%d3
        move.l %d2,-8(%a6)
        move.l %d3,-4(%a6)
        move.b 268444421,%d0
        moveq #0,%d4
        moveq #0,%d5
        move.b %d0,%d5
        move.l %d5,%d2
        clr.l %d3
        move.l -8(%a6),%d0
        or.l %d2,%d0
        move.l -4(%a6),%d1
        or.l %d3,%d1
        move.l %d0,-8(%a6)
        move.l %d1,-4(%a6)
        move.b 268444422,%d0
        moveq #0,%d4
        moveq #0,%d5
        move.b %d0,%d5
        move.l %d4,%d2
        move.l %d5,%d3
        asl.l #8,%d3
        mov.l %d3,%d2
        moveq #0,%d3
        move.l -8(%a6),%d0
        or.l %d2,%d0
        move.l -4(%a6),%d1
        or.l %d3,%d1
        move.l %d0,-8(%a6)
        move.l %d1,-4(%a6)
        move.l -8(%a6),%d2
        move.l -4(%a6),%d3
        move.l %d2,%d0
        move.l %d3,%d1
        jbra .L1
        .even
.L1:
        move.l -32(%a6),%d2
        move.l -28(%a6),%d3
        move.l -24(%a6),%d4
        move.l -20(%a6),%d5
        move.l -16(%a6),%d6
        move.l -12(%a6),%d7
        unlk %a6
        rts

changing the C source fixed that for now, but a compiler bug is a
compiler bug...

I hope anyone with compiler back-end experience can have a look at this.
I would
be happy to test any patches.

PS: egcs is better than gcc-2.8.1 for coldfire but still not perfect.

PPS: why not use:
.L1:
        movml (%sp),%d2-%d7
        unlk  %a6
        rts
for popping registers off the stack? Should be faster...

Kind regards,
Rolf

+-----------------+--------------------------------------------------+
|    _____        |  Rolf Fiedler                                    |
|   / ___/        |  Electronic Design Engineer                      |
|  / _/           |  Ferrari electronic AG                           |
| /_/e/r/r/a/r/i/ |  phone: +49 3328 4559 0   fax: +49 3328 4559 60  |
|   electronic    |  E-Mail: Rolf.Fiedler@Ferrari.DE                 |
+-----------------+--------------------------------------------------+
           "Where do you want to go tomorrow?"
_______________________________________________
New CrossGCC FAQ: http://www.objsw.com/CrossGCC
_______________________________________________
To remove yourself from the crossgcc list, send
mail to crossgcc-request@cygnus.com with the
text 'unsubscribe' (without the quotes) in the
body of the message.