How to resolve the algorithm Multiplication tables step by step in the AArch64 Assembly programming language
Published on 12 May 2024 09:40 PM
How to resolve the algorithm Multiplication tables step by step in the AArch64 Assembly programming language
Table of Contents
Problem Statement
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
Let's start with the solution:
Step by Step solution about How to resolve the algorithm Multiplication tables step by step in the AArch64 Assembly programming language
Source code in the aarch64 programming language
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program multtable64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ MAXI, 12
/*********************************/
/* Initialized data */
/*********************************/
.data
sMessValeur: .fill 11, 1, ' ' // size => 11
szCarriageReturn: .asciz "\n"
sBlanc1: .asciz " "
sBlanc2: .asciz " "
sBlanc3: .asciz " "
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
ldr x6,qAdrsBlanc1
ldr x7,qAdrsBlanc2
ldr x8,qAdrsBlanc3
// display first line
mov x4,#0
1: // begin loop
mov x0,x4
ldr x1,qAdrsMessValeur // display value
bl conversion10 // call function
strb wzr,[x1,x0] // final zéro on display value
ldr x0,qAdrsMessValeur
bl affichageMess // display message
cmp x4,#10 // one or two digit in résult
csel x0,x7,x8,ge // display 2 or 3 spaces
bl affichageMess // display message
add x4,x4,1 // increment counter
cmp x4,MAXI
ble 1b // loop
ldr x0,qAdrszCarriageReturn
bl affichageMess // display carriage return
mov x5,#1 // line counter
2: // begin loop lines
mov x0,x5 // display column 1 with N° line
ldr x1,qAdrsMessValeur // display value
bl conversion10 // call function
strb wzr,[x1,x0] // final zéro
ldr x0,qAdrsMessValeur
bl affichageMess // display message
cmp x5,#10 // one or two digit in N° line
csel x0,x7,x8,ge // display 2 or 3 spaces
bl affichageMess
mov x4,#1 // counter column
3: // begin loop columns
mul x0,x4,x5 // multiplication
mov x3,x0 // save résult
ldr x1,qAdrsMessValeur // display value
bl conversion10 // call function
strb wzr,[x1,x0]
ldr x0,qAdrsMessValeur
bl affichageMess // display message
cmp x3,100 // 3 digits in résult ?
csel x0,x6,x0,ge // display 1 spaces
bge 4f
cmp x3,10 // 2 digits in result
csel x0,x7,x8,ge // display 2 or 3 spaces
4:
bl affichageMess // display message
add x4,x4,1 // increment counter column
cmp x4,x5 // < counter lines
ble 3b // loop
ldr x0,qAdrszCarriageReturn
bl affichageMess // display carriage return
add x5,x5,1 // increment line counter
cmp x5,MAXI // MAXI ?
ble 2b // loop
100: // standard end of the program
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform the system call
qAdrsMessValeur: .quad sMessValeur
qAdrszCarriageReturn: .quad szCarriageReturn
qAdrsBlanc1: .quad sBlanc1
qAdrsBlanc2: .quad sBlanc2
qAdrsBlanc3: .quad sBlanc3
/******************************************************************/
/* Converting a register to a decimal unsigned */
/******************************************************************/
/* x0 contains value and x1 address area */
/* x0 return size of result (no zero final in area) */
/* area size => 11 bytes */
.equ LGZONECAL, 10
conversion10:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
stp x4,x5,[sp,-16]! // save registers
mov x3,x1
mov x2,#LGZONECAL
mov x4,10
1: // start loop
mov x5,x0
udiv x0,x5,x4
msub x1,x0,x4,x5 // x5 <- dividende. quotient ->x0 reste -> x1
add x1,x1,48 // digit
strb w1,[x3,x2] // store digit on area
cbz x0,2f // stop if quotient = 0
sub x2,x2,1 // else previous position
b 1b // and loop
// and move digit from left of area
2:
mov x4,0
3:
ldrb w1,[x3,x2]
strb w1,[x3,x4]
add x2,x2,1
add x4,x4,1
cmp x2,LGZONECAL
ble 3b
// and move spaces in end on area
mov x0,x4 // result length
mov x1,' ' // space
4:
strb w1,[x3,x4] // store space in area
add x4,x4,1 // next position
cmp x4,LGZONECAL
ble 4b // loop if x4 <= area size
100:
ldp x4,x5,[sp],16 // restaur 2 registers
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
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