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PowerPC: Problem with some assembler opcodes

Hello all, I'm using the powerpc-eabispe gcc version 3.4.4 and I want to initialize the decrenenter with the following code:

#include "mpc5500_spr.h"

union SPR_TCRVAL my_SPR_TCRVAL; union SPR_HID0VAL my_SPR_HID0VAL; /* Load initial DEC value */ asm volatile ("mtdec %[DEC]"::[DEC]"r"(configCPU_CLOCK_HZ / configTICK_RATE_HZ)); /* Load the same value into the reload register */ asm volatile ("mtdecar %[DECAR]"::[DECAR]"r"(configCPU_CLOCK_HZ / configTICK_RATE_HZ)); /* Enable decrementer interrupt */ my_SPR_TCRVAL.B.DIE = 1; /* Auto-reload enable */ my_SPR_TCRVAL.B.ARE = 1; asm volatile ("mttcr %[TCR]"::[TCR]"r"(my_SPR_TCRVAL)); /* Time base: 0 = processor clock, 1 = p_tbclk */ my_SPR_HID0VAL.B.SEL_TBCLK = 0; /* Enable the time base and decrementer */ my_SPR_HID0VAL.B.TBEN = 1; asm volatile ("mthid0 %[HID0]"::[HID0]"r"(my_SPR_HID0VAL));

The resulting error message is: Error: Unrecognized opcode: `mthid0'

than I tried the following:

asm volatile ("mtspr %[SPRHID0], %[HID0]"::[SPRHID0]"i"(SPR_HID0),[HID0]"r"(my_SPR_HID0VAL));

This compiles but the wornf code is generated, the dump of the elf-file:

asm volatile ("mtspr %[SPRHID0], %[HID0]"::[SPRHID0]"r"(SPR_HID0),[HID0]"r"(my_SPR_HID0VAL)); a920: 39 20 03 f0 li r9,1008 a924: 80 1f 00 0c lwz r0,12(r31) a928: 7c 09 03 a6 mtctr r0

Finally I tried it with the following line od code:

asm volatile ("mtspr 1008, r0"); a920: 7c 10 fb a6 mtdbsr r0

Why is mthid0 unkown and why is the compiler/assember generating the wrong code? How can I write into the HID0 Register with the gnu compiler?

Regards, Gilles

Reply to
Gilles
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gcc is not imported. The assembler (binutils) counts.

This is a 5554 specific registers. You might try using -mcpu=8540 in the commanline.

Did you lookup the real opcode ? Don't trust the disassembler here.

I use 3.4.4 gcc and 2.16.1 binutils and have no problem writing hid0 the above way.

--
42Bastian
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Reply to
42Bastian Schick

Until now I've always made an object dump from the elf and never looked to the real opcodes. What is the best procedure to do that?

My version of the Binutils is 2.15.91, the one that was on the cd that came with the P&E NEXUS. Is there a place where I can download ready to use GCC/Binutils/Newlib for the MPC55xx architecture?

Regards, Gilles

Reply to
Gilles

After analyzing the generated hex code: "7c 10 fb a6" I can conclude that the code itself is correct and that it must be a problem of the disassembler.

Do I have to specify a CPU when I'm analyzing the elf with powerpc-eabispe-objdump?

I'm still looking for a more recent version of the GCC/Binutils/Newlib.

Regards, Gilles

Reply to
Gilles

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