[Openec] checksum of first 64k of updateme.bin not calculated correctly
Frieder Ferlemann
frieder.ferlemann at web.de
Mon Nov 1 06:43:23 EDT 2010
Hi Richard,
Am 01.11.2010 10:04, schrieb Richard A. Smith:
> On 11/01/2010 03:56 AM, Frieder Ferlemann wrote:
>
>> Do you see problems/shortcomings (or near term problems)
>> with the current code?
>> (In terms of data, xdata, code memory or functionality?)
>
> The existing info out on IRC is a bit premature. I was waiting until
> after 1.75 bringup to write up the announcement and the general state of
> affairs.
Fine.
> Resource wise the KB3930 has plenty of resources, but its only a
> stepping stone. There are certainly some challenges ahead for moving to
> the IO3730. It only has 32k of ROM and does not have in-ram code
> execution ability.
>
> Right now it looks like we will have to switch back to Keil because sdcc
> generate code is so much larger.
How much space is left in data memory and in code memory?
(Can you give numbers for Keil versus SDCC?)
The memory model currently used (--model-large) for SDCC
is typically generating about 33% larger code than the
(--model-small) or about 18% larger code than the
stack-auto memory model.
(ratios from regression test results)
> Is sdcc 3 any better at generating smaller code?
If so then likely in the (low) single digit percent range.
BTW SDCC 3.0.0 has been released today.
The ec-1.75 source often uses code which clears/sets/
toggles bits within an external __xdata array.
SDCC does not recognize this yet.
Taking for example the last lines of the code generated
for updateme.c
1150 ; updateme.c:423: xbi[SPICFG] &= ~(SPICFG_WEN | SPICFG_CS_LOW);
0404 90 FE AD 1151 mov dptr,#(_xbi + 0x000d)
0407 E0 1152 movx a, at dptr
0408 FA 1153 mov r2,a
0409 53 02 E7 1154 anl ar2,#0xE7
040C 90 FE AD 1155 mov dptr,#(_xbi + 0x000d)
040F EA 1156 mov a,r2
0410 F0 1157 movx @dptr,a
These type of accesses could be reduced to:
1150 ; updateme.c:423: xbi[SPICFG] &= ~(SPICFG_WEN | SPICFG_CS_LOW);
0404 90 FE AD 1151 mov dptr,#(_xbi + 0x000d)
0407 E0 1152 movx a, at dptr
0409 xx E7 1154 anl a,#0xE7
040F xx 1156 mov r2,a
0410 F0 1157 movx @dptr,a
with relatively little effort by using a peephole file.
Greetings,
Frieder
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