System registers whose values are guaranteed

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FUNCTION CALL INTERFACE SPECIFICATIONS
Function Call Interface
System registers whose values are guaranteed

9.1.2 System registers whose values are guaranteed

(1)	Registers guaranteed to have the same values before and after function call

None

(2)	Registers guaranteed to have the same values before and after interrupts

Except for registers PSW and PC, there are no registers guaranteed to have the same values before and after an interrupt.Note

Note

Since MACR is not guaranteed to have the same values before and after an interrupt, it is recommended to use not MACH/MACHU instructions but the corresponding intrinsic functions to rewrite MACR. Because interrupts are disabled in these functions and then, multiply-accumulate operations using MACR are guaranteed to be executed correctly.