ATxmega128D4-AU ATMEL [ATMEL Corporation], ATxmega128D4-AU Datasheet - Page 11

• Manufacturer Part Number: ATxmega128D4-AU
• Description: 8/16-bit Atmel XMEGA D4 Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

6.8
8135L–AVR–06/12
Register File
by three. The return address is popped off the stack when returning from interrupts using the
RETI instruction, and from subroutine calls using the RET instruction.
The SP is decremented by one when data are pushed on the stack with the PUSH instruction,
and incremented by one when data is popped off the stack using the POP instruction.
To prevent corruption when updating the stack pointer from software, a write to SPL will auto-
matically disable interrupts for up to four instructions or until the next I/O memory write.
After reset the stack pointer is initialized to the highest address of the SRAM. See
page
The register file consists of 32 x 8-bit general purpose working registers with single clock cycle
access time. The register file supports the following input/output schemes:
• One 8-bit output operand and one 8-bit result input
• Two 8-bit output operands and one 8-bit result input
• Two 8-bit output operands and one 16-bit result input
• One 16-bit output operand and one 16-bit result input
Six of the 32 registers can be used as three 16-bit address register pointers for data space
addressing, enabling efficient address calculations. One of these address pointers can also be
used as an address pointer for lookup tables in flash program memory.
15.
XMEGA D4
Figure 7-2 on
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