Greetings!
I am trying to test the mrs ARM instruction from hello_world.c example using 2.95.3 toolchain, u-boot-1.1.1 (will update). SDRAM is at 0x30000000.
The C/assembly code is as follows:
#include <common.h> #include <exports.h>
int main (int argc, char *argv[]) { unsigned long *ptr1, *ptr2;
ptr1 = (unsigned long *) (0x30800000); ptr2 = (unsigned long *) (0x30800004);
asm volatile ("ldr r0,= 0x30800000"); asm volatile ("ldr r3,= 0x30800004"); asm volatile ("ldr r1,= 0xff000000"); asm volatile ("movs r2, r1, lsl #1"); asm volatile ("mrs r1, cpsr"); asm volatile ("str r1, [r0, #0]"); asm volatile ("str r2, [r3, #0]");
printf ("*ptr1 = %8lx\n", *ptr1); printf ("*ptr2 = %8lx\n", *ptr2);
return (0); }
I am expecting:
*ptr1 (0x30800000) = cpsr value *ptr2 (0x30800004) = 0xfe000000
I get the following output:
*ptr1 (0x30800000) = 0xfe000000 *ptr2 (0x30800004) = 0xfe000000
But, when I use md to get the memory dump, the values are correct though: 0x30800000 contains a00000d3 0x30800004 contains fe000000
a00000d3 = NzCvjIFt_svc
svc because I am using -D__KERNEL__ ?
Checking the disassembly using objdump reveals no instance of 0x30800004.
The Makefile, code, output is at: http://shakthimaan.com/616514.txt
I'd appreciate any inputs regarding this or am I missing something here.
Thanks,
SK
-- Shakthi Kannan, MS Software Engineer, Hexaware Technologies [E]: shakthimaan at yahoo dot com [M]: (91) 98407-87007 [W]: http://www.shakthimaan.com [L]: Chennai, India
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