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can't read CPSR correctly

arnina over 12 years ago

Note: This was originally posted on 15th October 2009 at http://forums.arm.com

hello,
I write the following codes to determine the mode in which the processor(Xscale) operates:

int x;
    asm volatile ("mrs %0, cpsr"
            :"=r"(x)
        );
    printf("cpsr:%x\n", x);

however, the result is:
cpsr:20000013

it doesn't seem to mean any mode, so what's going on?

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Bhaveet Shah over 12 years ago

Note: This was originally posted on 16th October 2009 at http://forums.arm.com

hello,
I write the following codes to determine the mode in which the processor(Xscale) operates:

however, the result is:
cpsr:20000013

it doesn't seem to mean any mode, so what's going on?

Sure it does... only the bottom 5 bits are the processor mode. Looking at: [url="http://infocenter.arm.com/help/topic/com.arm.doc.dui0204i/Chdddhea.html"]http://infocenter.arm.com/help/topic/com.a...i/Chdddhea.html[/url] the mode described by the above is 0b10011, which is supervisor.
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Bhaveet Shah over 12 years ago

Note: This was originally posted on 16th October 2009 at http://forums.arm.com

hello,
I write the following codes to determine the mode in which the processor(Xscale) operates:

however, the result is:
cpsr:20000013

it doesn't seem to mean any mode, so what's going on?

Sure it does... only the bottom 5 bits are the processor mode. Looking at: [url="http://infocenter.arm.com/help/topic/com.arm.doc.dui0204i/Chdddhea.html"]http://infocenter.arm.com/help/topic/com.a...i/Chdddhea.html[/url] the mode described by the above is 0b10011, which is supervisor.
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can&#39;t read CPSR correctly

can't read CPSR correctly