How do I identify the instruction stored LC-3
I know this is not a programming question but I am struggling to understand how to get the solution to this problem. I'm not sure how this is figured out and I can't find a explained solution.
The only change in the table is at address x3406. That tells us it was a store instruction as no other is capable of writing into memory.
The available store instructions are ST, STI and STR. ST uses a 9 bit signed offset from PC which is given as x3010 in the question and is therefore out of range. STI could work but we are not provided with a memory location usable for the indirect address. That leaves STR for which the encoding allows for a 6 bit offset so to make the address x3406 we need a base from x33E6 to x3427 which leaves only a single possibility: R4 for which the offset is 6.
The new value is xe373 which must have come from R2 since again that's the only option.
- Why does the ADD command in Donald Knuths number one program written on MIX set the overflow to ON?
- What does "int 0x80" mean in assembly code?
- What are the 128-bit to 512-bit registers used for?
- Making an absolute 64-bit jump in x64 assembler which can be copied as a JIT
- Segment Selector in IA-32
- Indirect addressing on P16F877
- Computing 2¹²⁸ % uint64_t
- How to read the content of ID_AA64MMFR1_EL1 register into the 64-bit variable using inline assembly?
- printf wont work when linking to ucrtbase.dll, but works when linked to msvcrt.dll (Windows, NASM)
- Do the bytes "00 10 A1 B3" make sense in Arm 32-bit architecture?
- Assembly code fail when I add a jump before rept
- 64-bit VMWare detection code triggers breakpoint
- What is the purpose of the k0, k1, ... k7 registers?
- How to generate an AVX-512 mask based on multiple comparisons of FP values in corresponding elements of vectors?
- Is assembly code and machine code part of the architecture?
- Do assembly instructions map 1-1 to machine language?
- Where do the compiler and assembler reside on a computer?
- Why does clang zero "eax" before calling a function with unspecified parameters, but gcc doesn't?
- Long long in c99
- What is the expansion of the MSR and MRS instructions in ARM
- How to correctly declare DCB in JCL/assembler for QSAM put-locate
- What does _SFR_IO8(0x04) is doing? AVR
- Linkgage between COBOL and HLASM (Assembly) with more than 32Kbytes
- Are rdi and rsi caller saved or callee saved registers?
- Using udf (undefined instruction) to check if the behavior is defined?
- Bootloader crashing when jumping to 0x100000
- Reason for (win) x64-calling convention restrictions in epilogues
- Difference between SHL and SAL in 80x86
- How does the LDA instruction interact with RAM and IR on MU1 architecture?
- How and why does my program change its input buffer? Using GDB to find out where. (Converting string to int in NASM x86 32bit)