Why shift a bit using sll and such in MIPs Assembly?

its pretty much just shifting all the bits left by 1

The example they showed was a shift by 1 bit. The sll instruction isn’t limited to just shifting by 1 bit; you can specify a shift amount in the range 0..31 (a shift by 0 might seem useless, but SLL $zero, $zero, 0 is used to encode a NOP on MIPS).

A logical left shift by N bits can be used as a fast means of multiplying by 2^N (2 to the power of N). So the instruction sll $t0, $s0, 2 is multiplying $s0 by 4 (2^2) and writing back to $t0. This is useful e.g. when scaling offsets to be used when accessing a word array.

Related Posts:

  1. Understanding how `lw` and `sw` actually work in a MIPS program
  2. MIPS: lw (load word) instruction
  3. MIPS assembly for a simple for loop
  4. mips .word function and differences between 2 codes
  5. Why doesn’t there exists a subi opcode for MIPS?
  6. What exactly does the lb instruction do?
  7. What is the difference between la and li in opcodes in MIPS?
  8. what is the use of ori in this part of MIPS code?
  9. Storing a user’s input in MIPS
  10. Integer absolute value in MIPS?
  11. MIPS Assembly – lui $t0, 4097?
  12. Greater than, less than equal, greater than equal in MIPS
  13. MIPS program jr $ra instructions and stack handling
  14. Subtract two input numbers
  15. Assembly language (MIPS) difference betweent addi and add
  16. MIPS Address out of range (MARS)
  17. Difference between “addi” and “add” for pseudoinstruction “move” in MIPS?
  18. sorting array in mips (assembly)
  19. Multiplication by a power of 2 using Logical shifts in MIPS assembly
  20. MIPS instruction and machine code
  21. Convert from Java to MIPS
  22. Understanding Assembly MIPS .ALIGN and Memory Addressing
  23. What’s the purpose of the LEA instruction?
  24. Understanding cmp instruction
  25. assembly “mov” instruction
  26. Assembly code vs Machine code vs Object code?
  27. What does the MOVZBL instruction do in IA-32 AT&T syntax?
  28. What’s the purpose of the LEA instruction?
  29. How to move ST(0) to EAX?
  30. The point of test %eax %eax
  31. Assembly: How does fld st(0) duplicates the top stack value in the following code?
  32. What does the MOVZBL instruction do in IA-32 AT&T syntax?
  33. What’s the purpose of the LEA instruction?
  34. The difference between cmpl and cmp
  35. x86 cmpl and jne
  36. What is the meaning of XOR in x86 assembly?
  37. What is the function of the push / pop instructions used on registers in x86 assembly?
  38. What is callq instruction?
  39. What does the BEQ instruction do exactly?
  40. What’s the size of a QWORD on a 64-bit machine?
  41. what does .space do in mips?
  42. Purpose of ESI & EDI registers?
  43. What are the ESP and the EBP registers?
  44. IDIV operation in assembly (understanding)
  45. Convert C program into assembly code
  46. LC3 LEA instruction and the value stored
  47. lc3 LDR instruction and the value stored
  48. What does movslq do?
  49. Assembly language je jump function
  50. Bubble sort algorithm in MIPS
  51. What are .S files?
  52. How do I correctly use the mod operator in MIPS?
  53. explanation about push ebp and pop ebp instruction in assembly
  54. Why are rbp and rsp called general purpose registers?
  55. x86 assembly: How does the ‘subl’ command work in AT&T syntax
  56. what does the cmpq instruction do?
  57. Purpose of ESI & EDI registers?
  58. Difference between “move” and “li” in MIPS assembly language
  59. Bubble sort on array on Assembly Language
  60. Nasm Error: invalid combination of opcode and operands
  61. When and why do we sign extend and use cdq with mul/div?
  62. Assembly addq clarification
  63. How do AX, AH, AL map onto EAX?
  64. writing functions in assembler
  65. pop or add esp, 4 ? What is the difference?
  66. What is the difference between MOV and LEA?
  67. `testl` eax against eax?
  68. Difference between JE/JNE and JZ/JNZ
  69. what is a file handle and where it is useful for a programmer?
  70. Printing out a number in assembly language?
  71. How does `Skipcond` work in the MARIE assembly language?
  72. What are callee and caller saved registers?
  73. What does `dword ptr` mean?
  74. Difference between JA and JG in assembly
  75. what does the the dword operand do in assembly
  76. What’s the difference between a word and byte?
  77. MIPS to C Translation
  78. Difference between movq and movabsq in x86-64
  79. What is the jmpq command doing in this example
  80. What does the LEAL assembly instruction do?
  81. Assembly – JZ instruction after CMP
  82. [Binary Bomb – Phase 4
  83. What does bx lr do in ARM assembly language?
  84. Difference between masm32 and masm?
  85. MIPS – Fetch address not aligned on word boundary
  86. Difference between JA and JG in assembly
  87. While, Do While, For loops in Assembly Language (emu8086)
  88. Mips how to store user input string
  89. movq assembly function
  90. x86 Assembly pointers
  91. xorl %eax – Instruction set architecture in IA-32
  92. Reading and printing an integer in mips
  93. Which variable size to use (db, dw, dd) with x86 assembly?
  94. Assembly x86 – “leave” Instruction
  95. JNZ & CMP Assembly Instructions
  96. Printing newline in MIPS
  97. What is the use of a $zero register in MIPS?
  98. Assembly Language – How to do Modulo?
  99. GDB no such file or directory
  100. `js` and `jb` instructions in assembly

Leave a Comment