assume the function
void foo(uint8_t value)
{
somearray[some_idx] = value;
}
CodeVision produces the following
ST -Y,R26 // the parameter "value" is in R26
; value -> Y+0
LDS R30,_some_idx
LDI R31,0
SUBI R30,LOW(-_somearray)
SBCI R31,HIGH(-_somearray)
LD R26,Y
STD Z+0,R26
The storing and loading of R26 to and from Y is completely unnecessary and is 2+2 cycles for nothing. I just want to understand why CodeVision is doing this, as it usually is very smart.