AW: [avr-gcc-list] Legal registers

[Haase Bjoern (PT-BEU/EMT) *]

For implementing, e.g. a context switch between two tasks you will have to safe 
*all* registers and the stack pointer. There is a distinction between different 
uses of the lower and the higher registers concerning the calling convention 
(the called function may safely overwrite a certain subset of registers without 
saving them), but that does not prevent gcc to take profit of all of the 
registers.

Yours,

Björn 

-----Ursprüngliche Nachricht-----
Von: address@hidden [mailto:address@hidden Im Auftrag von Ron
Gesendet: Sonntag, 5. Juni 2005 10:03
An: address@hidden
Betreff: [avr-gcc-list] Legal registers

Hi All. Does it somewhere specify that avrgcc and its library routines
should only use a subset of the AVR registers (say 0,1,18-31), or can
the whole 32 be used if required? I ask because it would save a deal of
pushing and popping in a preemptive os if you knew for sure register
subset x would never be used.

Ron Kreymborg



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