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--- en:multiasm:piot:chapter_4_5 [2026/03/01 19:38] – [Relative Program Memory Addressing] ktokarz
+++ en:multiasm:piot:chapter_4_5 [2026/03/01 19:43] (current) – [Addressing Modes] ktokarz
@@ Line 1: / Line 1: @@
 ====== Addressing Modes ======
-Addressing modes define how the processor accesses data. There are 15 different addressing modes, such as: Direct Addressing, Indirect Addressing, Indirect with Displacement, Immediate Addressing, Register Addressing, Relative Addressing, Indirect I/O Addressing, and Stack Addressing.
+Addressing modes define how the processor accesses data and the target address of a jump. There are more than a dozen different addressing modes, such as: Direct Addressing, Indirect Addressing, Indirect with Displacement, Immediate Addressing, Register Addressing, Relative Addressing, Indirect I/O Addressing, and others. In this section, we first present the data addressing and later addressing used in flow control instructions.
-Details on addressing modes are presented in Fig. {{ref>avr_addr_1}},{{ref>avr_addr_2}},{{ref>avr_addr_3}},{{ref>avr_addr_4}},{{ref>avr_addr_5}},{{ref>avr_addr_6}},{{ref>avr_addr_7}},{{ref>avr_addr_8}},{{ref>avr_addr_9}},{{ref>avr_addr_10}},{{ref>avr_addr_11}},{{ref>avr_addr_12}},{{ref>avr_addr_13}},{{ref>avr_addr_14}} and {{ref>avr_addr_15}}:
 =====Direct Single Register Addressing=====
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 =====Data Indirect Addressing=====
-Indirect addressing uses the content of an index register as a pointer to memory. As shown in Fig {{ref>avr_addr_5}}, the operand address is the contents of the X-, Y-, or Z-pointer. Please note that X is formed with concatenated registers R27 and R26, Y is built with R29 and R28, and Z with R31 and R30. In AVR devices without SRAM, Data Indirect Addressing is called Register Indirect Addressing.
+Indirect addressing uses the content of an index register as a pointer to memory. As shown in Fig {{ref>avr_addr_5}}, the operand address is the contents of the X, Y, or Z pointer. Please note that X is formed with concatenated registers R27 and R26, Y is built with R29 and R28, and Z with R31 and R30. In AVR devices without SRAM, Data Indirect Addressing is called Register Indirect Addressing.
 An example of the instruction is load data from memory addressed with an X pointer.
 <code asm>
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 =====Program Memory Constant Addressing=====
-With this addressing mode, it is possible to read the byte from the program memory. As shown in Fig {{ref>avr_addr_9}}, the byte address in program memory is determined by the value stored in the Z-pointer.
+With this addressing mode, it is possible to read the byte from the program memory. As shown in Fig {{ref>avr_addr_9}}, the byte address in program memory is determined by the value stored in the Z pointer.
 The upper 15 bits (Most Significant bits - MSbs) select the word address (each word contains 2 bytes).
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 =====Extended Indirect Program Memory Addressing=====
-For versions of AVR microcontrollers with bigger program memory than 128 kB, additional bits used to extend the address are stored in the EIND register. Program execution continues at the address contained by the Z-register and the EIND-register (i.e., the PC is loaded with the contents of the EIND and Z-register) as shown in fig {{ref>avr_addr_14}}.
+For versions of AVR microcontrollers with bigger program memory than 128 kB, additional bits used to extend the address are stored in the EIND register. Program execution continues at the address contained by the Z register and the EIND register (i.e., the PC is loaded with the contents of the EIND and Z register) as shown in fig {{ref>avr_addr_14}}.
 <figure avr_addr_14>

en/multiasm/piot/chapter_4_5.1772386717.txt.gz · Last modified: 2026/03/01 19:38 by ktokarz