/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program disMessGraph64.s   */
/* link with gcc options  -lX11 -L/usr/lpp/X11/lib */

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ ClientMessage, 33

/*******************************************/
/* Initialized data                        */
/*******************************************/
.data
szRetourligne: .asciz  "\n"
szMessErreur:  .asciz "Server X11 not found.\n"
szMessErrfen:  .asciz "Error create X11 window.\n"
szMessErrGC:   .asciz "Error create Graphic Context.\n"
szMessGoodBye: .asciz "Goodbye World!"

szLibDW:       .asciz "WM_DELETE_WINDOW"      // message close window

/*******************************************/
/* UnInitialized data                      */
/*******************************************/
.bss
.align 4
qDisplay:        .skip 8           // Display address
qDefScreen:      .skip 8           // Default screen address
identWin:        .skip 8           // window ident
wmDeleteMessage: .skip 16          // ident close message
stEvent:         .skip 400         // provisional size

buffer:          .skip 500

/**********************************************/
/* -- Code section                            */
/**********************************************/
.text
.global main                   // program entry
main:
    mov x0,#0                  // open server X
    bl XOpenDisplay
    cmp x0,#0
    beq erreur
                               //  Ok return Display address
    ldr x1,qAdrqDisplay
    str x0,[x1]                // store Display address for future use
    mov x28,x0                 // and in register 28
                               // load default screen
    ldr x2,[x0,#264]           // at location 264
    ldr x1,qAdrqDefScreen
    str x2,[x1]                //store default_screen
    mov x2,x0
    ldr x0,[x2,#232]           // screen list

                               //screen areas
    ldr x5,[x0,#+88]           // white pixel
    ldr x3,[x0,#+96]           // black pixel
    ldr x4,[x0,#+56]           // bits par pixel
    ldr x1,[x0,#+16]           // root windows
                               // create window x11
    mov x0,x28                 //display
    mov x2,#0                  // position X
    mov x3,#0                  // position Y
    mov x4,600                 // weight
    mov x5,400                 // height
    mov x6,0                   // bordure ???
    ldr x7,0                   // ?
    ldr x8,qBlanc              // background
    str x8,[sp,-16]!           // argument fot stack
    bl XCreateSimpleWindow
    add sp,sp,16               // for stack alignement
    cmp x0,#0                  // error ?
    beq erreurF
    ldr x1,qAdridentWin
    str x0,[x1]                // store window ident for future use
    mov x27,x0                 // and in register 27

                               // Correction of window closing error
    mov x0,x28                 // Display address
    ldr x1,qAdrszLibDW         // atom name address
    mov x2,#1                  // False  create atom if not exist
    bl XInternAtom
    cmp x0,#0
    ble erreurF
    ldr x1,qAdrwmDeleteMessage // address message
    str x0,[x1]
    mov x2,x1                  // address atom create
    mov x0,x28                 // display address
    mov x1,x27                 // window ident
    mov x3,#1                  // number of protocoles
    bl XSetWMProtocols
    cmp x0,#0
    ble erreurF
                               // create Graphic Context
    mov x0,x28                 // display address
    mov x1,x27                 // window ident
    bl createGC                // GC address -> x26
    cbz x0,erreurF
                               // Display window
    mov x1,x27                 // ident window
    mov x0,x28                 // Display address
    bl XMapWindow

    ldr x0,qAdrszMessGoodBye   // display text
    bl displayText

1:                             // events loop
    mov x0,x28                 // Display address
    ldr x1,qAdrstEvent         // events structure address
    bl XNextEvent
    ldr x0,qAdrstEvent         // events structure address
    ldr w0,[x0]                // type in 4 fist bytes
    cmp w0,#ClientMessage      // message for close window
    bne 1b                     // no -> loop

    ldr x0,qAdrstEvent         // events structure address
    ldr x1,[x0,56]             // location message code
    ldr x2,qAdrwmDeleteMessage // equal ?
    ldr x2,[x2]
    cmp x1,x2
    bne 1b                     // no loop

    mov x0,0                   // end Ok
    b 100f
erreurF:                       // error create window
    ldr x0,qAdrszMessErrfen
    bl affichageMess
    mov x0,1
    b 100f
erreur:                        // error no server x11 active
    ldr x0,qAdrszMessErreur
    bl affichageMess
    mov x0,1
100:                           // program standard end
    mov x8,EXIT
    svc 0
qBlanc:              .quad 0xF0F0F0F0
qAdrqDisplay:        .quad qDisplay
qAdrqDefScreen:      .quad qDefScreen
qAdridentWin:        .quad identWin
qAdrstEvent:         .quad stEvent
qAdrszMessErrfen:    .quad szMessErrfen
qAdrszMessErreur:    .quad szMessErreur
qAdrwmDeleteMessage: .quad wmDeleteMessage
qAdrszLibDW:         .quad szLibDW
qAdrszMessGoodBye:   .quad szMessGoodBye
/******************************************************************/
/*     create Graphic Context                                     */
/******************************************************************/
/* x0 contains the Display address */
/* x1 contains the ident Window */
createGC:
    stp x20,lr,[sp,-16]!       // save  registers
    mov x20,x0                 // save display address
    mov x2,#0
    mov x3,#0
    bl XCreateGC
    cbz x0,99f
    mov x26,x0                 // save GC
    mov x0,x20                 // display address
    mov x1,x26
    ldr x2,qRed                // code RGB color
    bl XSetForeground
    cbz x0,99f
    mov x0,x26                 // return GC
    b 100f
99:
    ldr x0,qAdrszMessErrGC
    bl affichageMess
    mov x0,0
100:
    ldp x20,lr,[sp],16         // restaur  2 registers
    ret                        // return to address lr x30
qAdrszMessErrGC:             .quad szMessErrGC
qRed:                        .quad 0xFF0000
qGreen:                      .quad 0xFF00
qBlue:                       .quad 0xFF
qBlack:                      .quad 0x0
/******************************************************************/
/*     display text on screen                                     */
/******************************************************************/
/* x0 contains the address of text */
displayText:
    stp x1,lr,[sp,-16]!    // save  registers
    mov x5,x0              // text address
    mov x6,0               // text size
1:                         // loop compute text size
    ldrb w10,[x5,x6]       // load text byte
    cbz x10,2f             // zero -> end
    add x6,x6,1            // increment size
    b 1b                   // and loop
2:
    mov x0,x28             // display address
    mov x1,x27             // ident window
    mov x2,x26             // GC address
    mov x3,#50             // position x
    mov x4,#100            // position y
    bl XDrawString
100:
    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"