Accelerator Manual (G06.27+, H06.04+, J06.03+)

Preparing Your Program for the Accelerator

Accelerator Manual—527303-003

3-5

Passing Parameters in Registers

fragment ending a procedure leaves a value on the register stack, although RP implies

that no value is returned.

PROC Q;

! Lots of code

CODE (LOAD L+3); ! Loads value on stack from data segment

CODE (STRP 7); ! Set RP=7, imply no value returned

CODE (EXIT);

When the PCAL instruction in the following fragment calls procedure Q, it uses the

value left on the register stack.

CODE (PCAL Q);

CODE (STRP 0); ! Set RP=0, use value on stack

CODE (STOR L+4); ! Stores value on stack to data segment

The Accelerator discards the LOAD L instruction, unless you specify ReturnsR0 Q to

tell the Accelerator to preserve that value.