Program And Data Addressing Modes - Atmel AVR AT90S4434 Preliminary

When using register indirect addressing modes with automatic pre-decrement and post-increment, the address registers X,
Y and Z are decremented and incremented.
The 32 general-purpose working registers, 64 I/O registers and the 256/512 bytes of internal data SRAM in the
AT90S4434/8535 are all accessible through all these addressing modes.
See the next section for a detailed description of the different addressing modes.

Program and Data Addressing Modes

The AT90S4434/8535 AVR RISC microcontroller supports powerful and efficient addressing modes for access to the pro-
gram memory (Flash) and data memory (SRAM, register file and I/O memory). This section describes the different
addressing modes supported by the AVR architecture. In the figures, OP means the operation code part of the instruction
word. To simplify, not all figures show the exact location of the addressing bits.
Register Direct, Single Register Rd
Figure 9. Direct Single Register Addressing
The operand is contained in register d (Rd).
Register Direct, Two Registers Rd And Rr
Figure 10. Direct Register Addressing, Two Registers
Operands are contained in register r (Rr) and d (Rd). The result is stored in register d (Rd).
AT90S/LS4434 and AT90S/LS8535
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