Avr movw. Instruction set avr35 is for classic AVR core plus MOVW, CALL, and JMP instructions (MCU types: attiny167, attiny1634, at90usb82, at90usb162, atmega8u2, atmega16u2, atmega32u2, ata5505). Update: gcc is targeting baseline AVR, so it can't use movw to copy a pair of registers. Although the AVR is an 8-bit architecture, there are a select few instructions that allow you to operate on 16-bit values (words). For example, the below code shows how to load the constant 0x1234 into r16 and r17, and copy it to r0 and r1. The AVR was one of the first microcontroller families to use on-chip flash memory for program storage. AVR® Instruction Set Manual Atmel AVR instruction set The Atmel AVR instruction set is the machine language for the Atmel AVR, a modified Harvard architecture 8-bit RISC single chip microcontroller which was developed by Atmel in 1996. The . The MOVW R26, R18 seems to have no affect and I never see the 65280 part. Jul 15, 2025 · The Load instructions are used to move data from memory to registers, while the Store instructions are used to move data from registers to memory. One of these is the instruction movw, which allows you to copy the contents of one register pair into another register pair. text . 10 Program Memory with Post-increment using the LPM Z+ and ELPM Z+ Instruction Nov 16, 2018 · So unless AVR gcc has a missed optimization, or there's some reason it's avoiding a word load, you can't do it. My question is is there something Support Microchip Forums AVR Freaks Design Help Technical Support Export Control Data The Atmel®megaAVR®8-bit Microcontrollers is a series of devices in the AVR®RISC Microcontroller family that includes, among other new enhancements, a hardware multiplier. I have a simple number that I have been playing with in assembler. 3. This just to learn and be comfortable with 32 bit numbers. 3242ba66 f6454118 movw r1, 0x5c18 // r1 = 0x5c18 3242ba6a 466f mov r7, sp 3242ba6c f6c0415a movt r1, 0xc5a // r1 = (r1 & 0xffff Assembly (AVR) Cheat Sheet Assembler Directives . The multiplier can handle both signed and unsigned integer and fractional numbers without speed or code size Apr 17, 2021 · MOVW命令の実装 次はMOVW命令です。 MOV命令は8ビット単位の転送でしたが、MOVW命令は2つの連続した汎用レジスタを16ビットのレジスタのように見立てて転送を行います。 こちらも 「AVR®命令一式手引書」 から命令の説明を引用します。 Introduction The megaAVR is a series of new devices in the AVR RISC Microcontroller family that includes, among other new enhancements, a hardware multiplier. Compiling with -mmcu=avr6 makes add(int*, int*) more efficient: add: movw r30,r24 # Z = a ld r24,Z ldd r25,Z+1 movw r30,r22 # Z = b ld r18,Z ldd Apr 15, 2021 · Hi all. data Registers r0 → freely available register that can be used for temporary values r1 → assume to always hold value of 0; must be cleared if used Caller-saved: r18 → r27, r30 → r31 Callee-saved: r2 → r17, r28 → r29 X → r27:r26 Y → r29:r28 Z → r31:r30 Jump Instructions breq - branch if equal (signed and unsigned Instruction set avr31 is for the classic AVR core with exactly 128K program memory space (MCU types: atmega103, at43usb320). Immediate instructions: AVR microcontrollers also support immediate instructions, which allow data to be loaded directly into a register without first storing it in memory. This multiplier is capable of multiplying two 8-bit numbers, giving a 16-bit result using only two clock cycles. It's the equivalent of OR-ing those two immediate values together, with the movt being the upper 16-bit. It seems the MOVW R24 , R18 gives me back the value of 517 (as expected). 0x00010105. In this case, r1 = (movt immediate value << 16) | (movw immediate value)). I manipulate it in assembler and return the value to Arduino. The multiplier can handle both signed and unsigned integer and fractional numbers without speed or code size penalty. set . Oct 17, 2011 · movw followed by a movt is a common way to load a 32-bit value into a register. eolmcdemtnslvbqzamjclqyuyvilvuqqcpoblusddqpujhkqsgvo