2.6 The Paper Computer

Paper computer Registers Memory!addresses ARM instruction set architectures ARM instruction set architectures!assembly language Assembly language!ARM Instructions Opcodes Processors The paper computer is a representation of a subset of a computer's registers and memory through time. In this section, we will examine a paper computer for an ARM processor to better understand our ARM programming model. The operation of the ARM processor will be explored by examining the execution of each step in the execution of a simple program.

Consider the program of Listing 2.1 written in the ARM "Unified Assembler Language" Arm (2014).

LDR R1, AUGEND ; load into register R1 from memory address labeled AUGEND LDR R2, ADDEND ; load into register R2 from memory address labeled ADDEND ADDS R2, R2, R1 ; assign the …