C868_02 Datasheet, PDF (21/244 Pages) Infineon Technologies AG – 8 - Bit CMOS Microcontroller

C868
Fundamental Structure
B Register
The B register is used during multiply and divide and serves as both source and
destination. For other instructions it can be treated as another scratch pad register.
Stack Pointer
The stack pointer (SP) register is 8 bits wide. It is incremented before data is stored
during PUSH and CALL executions and decremented after data is popped during a POP
and RET (RETI) execution, i.e. it always points to the last valid stack byte. While the
stack may reside anywhere in the on-chip RAM, the stack pointer is initialized to 07_H
after a reset. This causes the stack to begin a location = 08_H above register bank zero.
The SP can be read or written under software control.
User’s Manual
2-5
V 0.4, 2002-01