Messages in this thread |  | | Date | Wed, 13 Jun 2001 15:52:46 +0100 | From | Russell King <> | Subject | Re: [patch] 2.4.6-pre3 unresolved symbol do_softirq |
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On Wed, Jun 13, 2001 at 07:21:41AM -0700, David S. Miller wrote: > I can't believe there is no reliable way to get rid of that > pesky "$" gcc is adding to the symbol. Oh well...
GCC on ARM does a similar thing - all constants in the assembler are prefixed with '#' or '@'. Using the 'i' constraint adds this. This behaviour is actually useful when you want to pass a constant or a register - it allows GCC to make the decision for you, and do the right thing in the assembler fragment. Eg, the following code used to be in the kernel until 2.3:
extern __inline__ void __outb (unsigned int value, unsigned int port) { unsigned long temp; __asm__ __volatile__( "tst %2, #0x80000000\n\t" "mov %0, %4\n\t" "addeq %0, %0, %3\n\t" "strb %1, [%0, %2, lsl #2] @ outb" : "=&r" (temp) : "r" (value), "r" (port), "Ir" (PCIO_BASE - IO_BASE), "Ir" (IO_BASE) : "cc"); }
%3 and %4 might be a constant: mov r5, #0x03000000
or a real register if the constant can't be loaded in one instruction: mov r5, r1
'I' in this case means "a constant suitable for use with the arithmetic instructions".
-- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
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