The load and store instructions are for copying data between a register and a memory location. The load instruction copies data from a memory location to a register, whereas, the store instruction copies data from a register to a memory location. There are four different versions of the load and store instructions. They differ in how the address of
The Instruction Set Architecture (ISA) of the LC-3 is defined as follows: Memory address space 16 bits, corresponding to 216 locations, each containing one word (16 bits). Addresses are numbered from 0 (i.e, x0000) to 65,535 (i.e., xFFFF). Addresses are used to identify memory locations and memory-mapped I/O device registers.
Compute sum of 12 integers. Numbers start at location x3100.
All LC-3 programs begin with the .ORIG pseudo-op. Lines 4 and 5 are LC-3 instructions. The first instruction, loads the address of the “Hello World!” string and the next instruction prints the string to the console. It is not important to know how these instructions actually work right now, as they will be covered in the labs.
LC3 Instruction Set Architecture •The Instruction set architecture (ISA) of the LC3 o How is each instruction implemented by the control and data paths in the LC3 o Programming in machine code o How are programs executed §Memory layout, programs in machine code •Overview of LC3 microarchitecture o How are components connected to build the ...
LC-3 Instructions . LC-3 FSM . LC-3 Datapath . LC-3 Datapath Control Signals . cc figure +0P2 OP2 -NOT(SR MDR<-M MAR R7<-pc _pC+ To 49 ST -M 13 [BEN] PC & & Z. IR ARC MAR] MAR<-MDR —Base 18 18 I I 18 PC+0tt NOTES MAR] ARC MAR<-MDR 18 18 set CC 18 FC+0ffg pc SEXT{offsetg] : pc + SEXTIoffsA11
ISA provides all information needed for someone that wants to write a program in machine language (or translate from a high-level language to machine language). Calls a service routine, identified by 8-bit “trap vector.” When routine is done, PC is set to the instruction following TRAP. (We’ll talk about how this works later.)
On the following pages, the instructions will be described in greater detail. For each instruction, we show the assembly language representation, the format of the 16-bit instruction, the operation of the instruction, an English-languagedescription …
Figure A.2 Format of the entire LC-3 instruction set. Note: + indicates instructions that modify condition codes
A branch instruction specifies when a branch will be taken by its IR.nzp bits, IR[11:9]. If a non-zero IR.nzp bit matches the non-zero PSR.NZP bit, the branch it taken.