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Inside Macintosh: Devices /
Chapter 2 - Slot Manager / Slot Manager Reference
Low-Level Routines /


This function is used only by the Macintosh Operating System.

FUNCTION SCalcStep (spBlkPtr: SpBlockPtr): OSErr;
A pointer to a Slot Manager parameter block.
<--spResultLongIntThe function result.
-->spsPointerPtrA pointer to a byte in declaration ROM.
-->spByteLanesSignedByteThe byte lanes used.

The SCalcStep function calculates the field sizes in the block pointed to by spBlkPtr. It is used for stepping through the card firmware one field at a time. If the fConsecBytes flag is set the function calculates the step value for consecutive bytes; otherwise it calculates it for consecutive IDs.

The trap macro and routine selector for the SCalcStep function are
Trap macroSelector

On entry, register D0 contains the routine selector and register A0 contains the address of the Slot Manager parameter block. When _SlotManager returns, register D0 contains the result code.
Registers on entry
A0Address of the parameter block
Registers on exit
D0Result code

noErr0No error
smNoMoresRsrcs-344Requested sResource not found

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© Apple Computer, Inc.
3 JUL 1996