/* ARM assembly Raspberry PI */ /* program loopnested.s */ /************************************/ /* Constantes */ /************************************/ .equ STDOUT, 1 @ Linux output console .equ EXIT, 1 @ Linux syscall .equ WRITE, 4 @ Linux syscall .equ NBVALUECOL, 10 .equ NBLIGNES, 10 .equ MAXVALUE, 20 /*********************************/ /* Initialized data */ /*********************************/ .data sMessResult: .ascii " " sMessValeur: .fill 11, 1, ' ' @ size => 11 szCarriageReturn: .asciz "\n" .align 4 iGraine: .int 314159 /*********************************/ /* UnInitialized data */ /*********************************/ .bss tiValues: .skip 4 * NBVALUECOL * NBLIGNES /*********************************/ /* code section */ /*********************************/ .text .global main main: @ entry of program ldr r3,iAdrtiValues mov r4,#0 @ loop indice mov r5,#0 mov r7,#4 * NBVALUECOL 1: @ begin loop 1 mov r0,#MAXVALUE + 1 bl genereraleas @ result 0 to MAXVALUE mul r6,r5,r7 add r6,r4,lsl #2 str r0,[r3,r6] add r4,#1 cmp r4,#NBVALUECOL blt 1b mov r4,#0 add r5,#1 cmp r5,#NBLIGNES blt 1b mov r4,#0 @ loop indice mov r5,#0 @ total ldr r3,iAdrtiValues @ table values address 2: mul r6,r5,r7 add r6,r4,lsl #2 ldr r0,[r3,r6] ldr r1,iAdrsMessValeur @ display value bl conversion10 @ call conversion decimal mov r1,#0 ldr r0,iAdrsMessResult strb r1,[r0,#4] ldr r0,iAdrsMessResult bl affichageMess @ display message ldr r0,[r3,r6] cmp r0,#MAXVALUE beq 3f add r4,#1 cmp r4,#NBVALUECOL blt 2b ldr r0,iAdrszCarriageReturn bl affichageMess @ display message mov r4,#0 add r5,#1 cmp r5,#NBLIGNES blt 2b b 100f 3: ldr r0,iAdrszCarriageReturn bl affichageMess @ display message 100: @ standard end of the program mov r0, #0 @ return code mov r7, #EXIT @ request to exit program svc #0 @ perform the system call iAdrsMessValeur: .int sMessValeur iAdrszCarriageReturn: .int szCarriageReturn iAdrsMessResult: .int sMessResult iAdrtiValues: .int tiValues /******************************************************************/ /* display text with size calculation */ /******************************************************************/ /* r0 contains the address of the message */ affichageMess: push {r0,r1,r2,r7,lr} @ save registres mov r2,#0 @ counter length 1: @ loop length calculation ldrb r1,[r0,r2] @ read octet start position + index cmp r1,#0 @ if 0 its over addne r2,r2,#1 @ else add 1 in the length bne 1b @ and loop @ so here r2 contains the length of the message mov r1,r0 @ address message in r1 mov r0,#STDOUT @ code to write to the standard output Linux mov r7, #WRITE @ code call system "write" svc #0 @ call systeme pop {r0,r1,r2,r7,lr} @ restaur des 2 registres */ bx lr @ return /******************************************************************/ /* Converting a register to a decimal unsigned */ /******************************************************************/ /* r0 contains value and r1 address area */ /* r0 return size of result (no zero final in area) */ /* area size => 11 bytes */ .equ LGZONECAL, 10 conversion10: push {r1-r4,lr} @ save registers mov r3,r1 mov r2,#LGZONECAL 1: @ start loop bl divisionpar10U @ unsigned r0 <- dividende. quotient ->r0 reste -> r1 add r1,#48 @ digit strb r1,[r3,r2] @ store digit on area cmp r0,#0 @ stop if quotient = 0 subne r2,#1 @ else previous position bne 1b @ and loop @ and move digit from left of area mov r4,#0 2: ldrb r1,[r3,r2] strb r1,[r3,r4] add r2,#1 add r4,#1 cmp r2,#LGZONECAL ble 2b @ and move spaces in end on area mov r0,r4 @ result length mov r1,#' ' @ space 3: strb r1,[r3,r4] @ store space in area add r4,#1 @ next position cmp r4,#LGZONECAL ble 3b @ loop if r4 <= area size 100: pop {r1-r4,lr} @ restaur registres bx lr @return /***************************************************/ /* division par 10 unsigned */ /***************************************************/ /* r0 dividende */ /* r0 quotient */ /* r1 remainder */ divisionpar10U: push {r2,r3,r4, lr} mov r4,r0 @ save value //mov r3,#0xCCCD @ r3 <- magic_number lower raspberry 3 //movt r3,#0xCCCC @ r3 <- magic_number higter raspberry 3 ldr r3,iMagicNumber @ r3 <- magic_number raspberry 1 2 umull r1, r2, r3, r0 @ r1<- Lower32Bits(r1*r0) r2<- Upper32Bits(r1*r0) mov r0, r2, LSR #3 @ r2 <- r2 >> shift 3 add r2,r0,r0, lsl #2 @ r2 <- r0 * 5 sub r1,r4,r2, lsl #1 @ r1 <- r4 - (r2 * 2) = r4 - (r0 * 10) pop {r2,r3,r4,lr} bx lr @ leave function iMagicNumber: .int 0xCCCCCCCD /***************************************************/ /* Generation random number */ /***************************************************/ /* r0 contains limit */ genereraleas: push {r1-r4,lr} @ save registers ldr r4,iAdriGraine ldr r2,[r4] ldr r3,iNbDep1 mul r2,r3,r2 ldr r3,iNbDep1 add r2,r2,r3 str r2,[r4] @ maj de la graine pour l appel suivant cmp r0,#0 beq 100f mov r1,r0 @ divisor mov r0,r2 @ dividende bl division mov r0,r3 @ résult = remainder 100: @ end function pop {r1-r4,lr} @ restaur registers bx lr @ return /*****************************************************/ iAdriGraine: .int iGraine iNbDep1: .int 0x343FD iNbDep2: .int 0x269EC3 /***************************************************/ /* integer division unsigned */ /***************************************************/ division: /* r0 contains dividend */ /* r1 contains divisor */ /* r2 returns quotient */ /* r3 returns remainder */ push {r4, lr} mov r2, #0 @ init quotient mov r3, #0 @ init remainder mov r4, #32 @ init counter bits b 2f 1: @ loop movs r0, r0, LSL #1 @ r0 <- r0 << 1 updating cpsr (sets C if 31st bit of r0 was 1) adc r3, r3, r3 @ r3 <- r3 + r3 + C. This is equivalent to r3 ? (r3 << 1) + C cmp r3, r1 @ compute r3 - r1 and update cpsr subhs r3, r3, r1 @ if r3 >= r1 (C=1) then r3 <- r3 - r1 adc r2, r2, r2 @ r2 <- r2 + r2 + C. This is equivalent to r2 <- (r2 << 1) + C 2: subs r4, r4, #1 @ r4 <- r4 - 1 bpl 1b @ if r4 >= 0 (N=0) then loop pop {r4, lr} bx lr