Bug#494010: Source for dsp56k firmware
On Thu, Oct 16, 2008 at 12:32:15AM +0100, Ben Hutchings wrote:
> > - Attached patch fixes a few errors spit by a56. I think my other two fixes
> > are correct, but I have no idea what the '<' / '>' candy is supposed to do
> > (hints?).
>
> According to the assembler reference manual
> <http://www.freescale.com/files/dsp/doc/ref_manual/DSPASMRM.pdf> they mean:
>
> << - I/O short addressing mode force operator
> < - Short addressing mode force operator
> > - Long addressing mode force operator
Thanks. This seems to be a non-issue (resulting code is the same, indicating
a56 already makes the same assumptions).
> > - Resulting offsets doen't match with the blob. I still haven't figured out
> > how are program code offsets mapped to the output file, but some parts
> > don't match. For example, the blob has a jump (0C 00 40) to 0x40
> > (and so does a56 output, at offset 0x0 in both cases), but then code
> > from the blob continues at 0xc0, unlike code from a56 which continues at
> > 0x40. Is there some trick to this?
>
> It's a 24-bit processor and uses word-addressing, not byte-addressing.
Ok, fixed that. I got a 100% code match now. The only remaining question is
what's the deal with this section that's supposed to start at 0x7ea9 but
actually starts at 0x4f (0xed in the file). My code adds a workaround for
that:
if (offset > 0x7000)
offset -= 0x7e5a;
which is really nasty. Anyone knows better?
--
Robert Millan
The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
how) you may access your data; but nobody's threatening your freedom: we
still allow you to remove your data and not access it at all."
- Remove '<' and '>' candy (they specify explicit addressing modes,
which a56 don't grok, but uses follows implicitly anyway).
- Replace 'move' with 'movem' when accessing program memory.
- Rename a few labels to avoid duplicates (which a56 can't handle).
--- ../bootstrap.asm.old 2008-10-15 18:22:56.000000000 +0200
+++ ../bootstrap.asm 2008-10-16 15:53:29.000000000 +0200
@@ -51,19 +51,19 @@
; Copy DSP program control
move #real,r0
move #upload,r1
- do #upload_end-upload,<_copy
- move P:(r0)+,x0
- move x0,P:(r1)+
-_copy movep #>4,X:<<M_HCR
- movep #>$c00,X:<<M_IPR
+ do #upload_end-upload,_copy
+ movem P:(r0)+,x0
+ movem x0,P:(r1)+
+_copy movep #4,X:<<M_HCR
+ movep #$c00,X:<<M_IPR
and #<$fe,mr
jmp upload
real
org P:$7ea9
upload
- movep #>1,X:<<M_PBC
- movep #>0,X:<<M_BCR
+ movep #1,X:<<M_PBC
+ movep #0,X:<<M_BCR
next jclr #0,X:<<M_HSR,*
movep X:<<M_HRX,A
@@ -81,18 +81,18 @@
cmp x0,A
jeq load_Y
-load_P do y0,_load
+load_P do y0,_load_P
jclr #0,X:<<M_HSR,*
movep X:<<M_HRX,P:(r0)+
-_load jmp next
-load_X do y0,_load
+_load_P jmp next
+load_X do y0,_load_X
jclr #0,X:<<M_HSR,*
movep X:<<M_HRX,X:(r0)+
-_load jmp next
-load_Y do y0,_load
+_load_X jmp next
+load_Y do y0,_load_Y
jclr #0,X:<<M_HSR,*
movep X:<<M_HRX,Y:(r0)+
-_load jmp next
+_load_Y jmp next
upload_end
end
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
main (int argc, char *argv[])
{
unsigned int offset;
unsigned int native_value;
int fd;
uint8_t value[3];
char type;
char *line = NULL;
size_t zero = 0;
if (argc != 2)
{
fprintf (stderr, "Usage: %s output < input\n", argv[0]);
exit (1);
}
fd = open (argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0644);
while (getline (&line, &zero, stdin) != -1)
{
sscanf (line, "%c ", &type);
if (type != 'P')
continue;
sscanf (line + 2, "%x %x\n", &offset, &native_value);
value[0] = (native_value >> 16) & 0xff;
value[1] = (native_value >> 8) & 0xff;
value[2] = native_value & 0xff;
// FIXME
if (offset > 0x7000)
offset -= 0x7e5a;
pwrite (fd, value, 3, (off_t) (offset * 3));
}
close (fd);
exit (0);
}
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