/* ===============================

   This program uses codes from Rosetta Code.
   See: https://rosettacode.org/wiki/Tokenize_a_string
   This code follows Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

   =============================== */

/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program tokenize_string.s   */
 
/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
 
.equ NBPOSTESECLAT,          20
 
/*******************************************/
/* Initialized data                        */
/*******************************************/
.data
szMessFinal:         .asciz "Words are : \n"
 
szString:            .asciz "Hello,How,Are,You,Today"
szMessError:         .asciz "Error tokenize !!\n"
szCarriageReturn:    .asciz "\n"
/*******************************************/
/* UnInitialized data                      */
/*******************************************/
.bss 
/*******************************************/
/*  code section                           */
/*******************************************/
.text
.global main 
main: 
    ldr x0,qAdrszString                           // string address 
    mov x1,','                                    // separator
    bl stTokenize
    cmp x0,-1                                     // error ?
    beq 99f
    mov x2,x0                                     // table address
    ldr x0,qAdrszMessFinal                        // display message
    bl affichageMess
    ldr x4,[x2]                                   // number of areas
    add x2,x2,8                                   // first area
    mov x3,0                                      // loop counter
    mov x0,x2
1:                                                // display loop 
    ldr x0,[x2,x3, lsl 3]                         // address area
    bl affichageMess
    ldr x0,qAdrszCarriageReturn                   // display carriage return
    bl affichageMess
    add x3,x3,1                                  // counter + 1
    cmp x3,x4                                     // end ?
    blt 1b                                        // no -> loop
 
    b 100f
99:                                               // display error message
    ldr x0,qAdrszMessError
    bl affichageMess
 
100:                                              // standard end of the program
    mov x0,0                                       // return code
    mov x8,EXIT                                   // request to exit program
    svc 0                                         // perform the system call
qAdrszString:             .quad szString
//qAdrszFinalString:        .quad szFinalString
qAdrszMessFinal:          .quad szMessFinal
qAdrszMessError:          .quad szMessError
qAdrszCarriageReturn:     .quad szCarriageReturn
 
/*******************************************************************/	   
/* Separate string by separator into an array                     */
/* areas are store on the heap Linux                               */
/*******************************************************************/	  
/* x0 contains string address */
/* x1 contains separator character (, or . or : )    */
/* x0 returns table address with first item = number areas */
/* and other items contains pointer of each string     */
stTokenize:
    stp x1,lr,[sp,-16]!           // save  registers
    mov x16,x0
    mov x9,x1                     // save separator
    mov x14,0          
1:                                // compute length string for place reservation on the heap
    ldrb w12,[x0,x14]
    cbz x12, 2f
    add x14,x14,1
    b 1b
2:
    ldr x12,qTailleTable
    add x15,x12,x14
    and x15,x15,0xFFFFFFFFFFFFFFF0
    add x15,x15,16                 // align word on the heap
                                  // place reservation on the heap 
    mov x0,0                      // heap address
    mov x8,BRK                    // call system linux 'brk'
    svc 0                         // call system
    cmp x0,-1                     // error call system
    beq 100f
    mov x14,x0                    // save address  heap begin = begin array
    add x0,x0,x15                 // reserve x15 byte on the heap
    mov x8,BRK                    // call system linux 'brk'
    svc 0
    cmp x0,-1
    beq 100f
                                  // string copy on the heap
    add x13,x14,x12               // behind the array 
    mov x0,x16
    mov x1,x13
3:                                // loop copy string
    ldrb w12,[x0],1               // read one byte and increment pointer one byte
    strb w12,[x1],1               // store one byte and increment pointer one byte
    cbnz x12,3b                   // end of string ? no -> loop 
 
    mov x0,#0
    str x0,[x14]
    str x13,[x14,8]
    mov x12,#1                     // areas counter
4:                                // loop load string character 
    ldrb w0,[x13]
    cbz x0,5f                     // end string 
    cmp x0,x9                     // separator ?
    cinc x13,x13,ne               // no -> next location 
    bne 4b                        // and loop
    strb wzr,[x13]                // store zero final of string
    add x13,x13,1                 // next character
    add x12,x12,1                 // areas counter + 1
    str x13,[x14,x12, lsl #3]     // store address area in the table at index x2
    b 4b                          // and loop
 
5:
    str x12,[x14]                 // store number areas
    mov x0,x14                    // returns array address
100:
    ldp x1,lr,[sp],16             // restaur  2 registers
    ret                           // return to address lr x30
qTailleTable:      .quad 8 * NBPOSTESECLAT
 
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"