/* ARM assembly Raspberry PI  */
/*  program sysTime.s   */

/* REMARK 1 : this program use routines in a include file
   see task Include a file language arm assembly
   for the routine affichageMess conversion10
   see at end of this program the instruction include */

/*******************************************/
/* Constantes                              */
/*******************************************/
.equ STDOUT, 1           @ Linux output console
.equ EXIT,   1           @ Linux syscall
.equ WRITE,  4           @ Linux syscall
.equ BRK,    0x2d        @ Linux syscall
.equ CHARPOS,     '@'

.equ GETTIME,   0x4e     @ call system linux gettimeofday

/*******************************************/
/* Structures                               */
/********************************************/
/* example structure  time  */
    .struct  0
timeval_sec:                     @
    .struct  timeval_sec + 4
timeval_usec:                     @
    .struct  timeval_usec + 4
timeval_end:
    .struct  0
timezone_min:                     @
    .struct  timezone_min + 4
timezone_dsttime:                 @
    .struct  timezone_dsttime + 4
timezone_end:

/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessError:       .asciz "Error detected !!!!. \n"
szMessResult:      .asciz "GMT: @/@/@  @:@:@  @ms\n"  @ message result

szCarriageReturn:  .asciz "\n"
.align 4
tbDayMonthYear:    .int  0,  31,  60,  91, 121, 152, 182, 213, 244, 274, 305, 335
                   .int 366, 397, 425, 456, 486, 517, 547, 578, 609, 639, 670, 700
                   .int 731, 762, 790, 821, 851, 882, 912, 943, 974,1004,1035,1065
                   .int 1096,1127,1155,1186,1216,1247,1277,1308,1339,1369,1400,1430
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
.align 4
stTVal:                .skip timeval_end
stTZone:               .skip timezone_end
sZoneConv:             .skip 100
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                              @ entry of program
    ldr r0,iAdrstTVal
    ldr r1,iAdrstTZone
    mov r7,#GETTIME
    svc 0
    cmp r0,#-1                     @ error ?
    beq 99f
    ldr r0,iAdrstTVal
    ldr r1,[r0,#timeval_sec]       @ timestemp in second
    //ldr r1,iTStest1
    //ldr r1,iTStest2
    //ldr r1,iTStest3
    ldr r2,iSecJan2020
    sub r0,r1,r2                   @ total secondes to 01/01/2020
    mov r1,#60
    bl division
    mov r0,r2
    mov r6,r3                      @ compute secondes
    mov r1,#60
    bl division
    mov r7,r3                      @ compute minutes
    mov r0,r2
    mov r1,#24
    bl division
    mov r8,r3                      @ compute hours
    mov r0,r2
    mov r11,r0
    mov r1,#(365 * 4 + 1)
    bl division
    lsl r9,r2,#2                   @ multiply by 4 = year1
    mov r1,#(365 * 4 + 1)
    mov r0,r11
    bl division
    mov r10,r3
    ldr r1,iAdrtbDayMonthYear
    mov r2,#3
    mov r3,#12
1:
    mul r11,r3,r2
    ldr r12,[r1,r11,lsl #2]         @ load days by year
    cmp r10,r12
    bge 2f
    sub r2,r2,#1
    cmp r2,#0
    bne 1b
2:                                 @ r2 = year2
    mov r5,#11
    mul r4,r3,r2
    lsl r4,#2
    add r4,r1
3:
    ldr r12,[r4,r5,lsl #2]         @ load days by month
    cmp r10,r12
    bge 4f
    subs r5,r5,#1
    bne 3b
4:                                 @ r5 = month - 1
    mul r11,r3,r2
    add r11,r5
    ldr r1,iAdrtbDayMonthYear
    ldr r3,[r1,r11,lsl #2]
    sub r0,r10,r3

    add r0,r0,#1                   @ final compute day
    ldr r1,iAdrsZoneConv
    bl conversion10                @ this function do not zero final
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    ldr r0,iAdrszMessResult
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at first @ character
    mov r3,r0
    add r0,r5,#1                   @ final compute month
    ldr r1,iAdrsZoneConv
    bl conversion10
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    mov r0,r3
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at next @ character
    mov r3,r0
    ldr r11,iYearStart
    add r0,r9,r11
    add r0,r0,r2                   @ final compute year = 2020 + year1 + year2
    ldr r1,iAdrsZoneConv
    bl conversion10
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    mov r0,r3
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at next @ character
    mov r3,r0
    mov r0,r8                      @ hours
    ldr r1,iAdrsZoneConv
    bl conversion10
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    mov r0,r3
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at next @ character
    mov r3,r0
    mov r0,r7                      @ minutes
    ldr r1,iAdrsZoneConv
    bl conversion10
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    mov r0,r3
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at next @ character
    mov r3,r0
    mov r0,r6                      @ secondes
    ldr r1,iAdrsZoneConv
    bl conversion10
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    mov r0,r3
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at next @ character
    mov r3,r0
    ldr r1,iAdrstTVal
    ldr r0,[r1,#timeval_usec]      @ millisecondes
    ldr r1,iAdrsZoneConv
    bl conversion10
    mov r4,#0                      @ store zero final
    strb r4,[r1,r0]
    mov r0,r3
    ldr r1,iAdrsZoneConv
    bl strInsertAtCharInc          @ insert result at next @ character
    bl affichageMess
    b 100f
99:
    ldr r0,iAdrszMessError
    bl affichageMess
100:                               @ standard end of the program
    mov r0,#0                      @ return code
    mov r7,#EXIT                   @ request to exit program
    svc 0                          @ perform the system call

iAdrszMessError:          .int szMessError
iAdrstTVal:               .int stTVal
iAdrstTZone:              .int stTZone
iAdrszMessResult:         .int szMessResult
iAdrszCarriageReturn:     .int szCarriageReturn
iAdrsZoneConv:            .int sZoneConv
iSecJan2020:              .int 1577836800
iAdrtbDayMonthYear:       .int tbDayMonthYear
iYearStart:               .int 2020
iTStest1:                 .int 1609508339    @ 01/01/2021
iTStest2:                 .int 1657805939    @ 14/07/2022
iTStest3:                 .int 1767221999    @ 31/12/2025
/***************************************************/
/*      ROUTINES INCLUDE                 */
/***************************************************/
.include "../affichage.inc"