URL:
<http://savannah.nongnu.org/bugs/?18373>
Summary: Bugs in Inline ASM documentacion
Project: AVR C Runtime Library
Submitted by: None
Submitted on: Saturday 11/25/2006 at 14:45 UTC
Category: Documentation
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: None
Status: None
Privacy: Public
Assigned to: None
Percent Complete: 0%
Originator Email: [EMAIL PROTECTED]
Open/Closed: Open
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Details:
1. In section about inline asm you write that compiler doesn't support
Read-Write operand. It isn't true. Checked.
2. There is simpler way to acces operands than by number. You can write sth
like this:
static inline void delayus8(uint8_t t)
{
asm volatile(
"delayus8_loop%=: \n\t"
"nop \n\t"
"dec %[ticks] \n\t"
"brne delayus8_loop%= \n\t"
:[ticks]"+r"(t)
:
);
}
There is no need to make the same register as input and output because of
"+r" - read-write operand. But if you want, you can make it this way:
asm volatile(
"delayus8_loop%=: \n\t"
"nop \n\t"
"dec %[ticks] \n\t"
"brne delayus8_loop%= \n\t"
:[ticks]"=r"(t)
:"ticks"(t)
);
But I found that it doesent always work correctly. It is compiled like
compiler "think" it dont need to set register [ticks] before call asembler
section.
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