Basic System Problem Analysis - August 2003

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page 193/17/2003
Basic System Problem Analysis
Procedure Calling Convention: SP & PSP
Once the STWM (or LDO) instruction is executed to build a
new stack frame, all references to a procedure’s parameters
become “PSP” (previous stack pointer) relative.
GR26 to GR23 may be spilled to PSP-$24 to PSP-$30
respectively.
You cannot count on that occurring! There may be no need to
save a register to memory.
Notes: