.syntax unified
.global main

.type main, %function
main:
  bl init
  b restart

restart:
  mov r0,0        @initialize r0 to be played
  mov r4,0        @a reference register as the current peak

  ldr r6, =array  @Loading the array location
  ldr r7, [r6, 4] @Loading the first element on the array
  mov r5, r7      @Use r5 as a reference from the first element
  ldr r8, [r6]    @Size of the array
  mov r9, 1     @Array Counter
  mov r10, 12000@Duration for 0.25
  mov r11, 0    @Duration Counter

  b positive_peak

positive_peak:    @Label that change r6 to positive peak

  ldr r4, =0x7fff @Setting the positive peak at 0x7fff
  mov r0, r4      @Putting the positive peak value to r0 to be played
  add r11, 1
  cmp r10, r11
  beq change_pitch
  sub r7, 1        @Adding 1 to the counter
  cmp r7, 0      @Because the Period = 1/f and the BSP is 48khz then to get the period for 1/440HZ we multiply is by 48khz
                  @which will reslted with 109.090909
                  @But we need the point for half of a period because each peak is only half a period
                  @which is 54.5 but since we can't use float in integer then we use 55
  beq negative_peak @This will change the peak to negative peak if high peak has reach the half period
  bl BSP_AUDIO_OUT_Play_Sample @This will play the sound at the particular value of r0

b positive_peak

negative_peak:  @Label that change r6 to positive peak

  ldr r4, =0x8000 @Setting the negative peak at 0x7fff
  mov r0, r4      @Putting the negative peak value to r0 to be played
  add r11, 1
  cmp r10, r11
  beq change_pitch
  add r7, 1      @Substracting 1 to the counter
  cmp r7, r5
  @ bleq change
                  @when the subs reach 0 then the negative peak has reach half of the period which is 55 then we change it to positive
  beq positive_peak
  bl BSP_AUDIO_OUT_Play_Sample

 b negative_peak


change_pitch:
  add r9, 1
  cmp r8, r9
  beq restart
  mov r12, 4
  mul r3, r9, r12
  ldr r7, [r6,r3]
  mov r10, 12000@Duration for 0.25
  mov r11, 0    @Duration Counter
  b positive_peak

.data
array:
  .word 27
  .word 82, 0, 69, 0, 61, 61, 0, 82, 0, 69, 0, 58, 61, 61, 0, 0, 82, 0, 69, 0, 61, 61 , 0, 69, 0, 82, 0


@ print(cal(293.66));
@ print(cal(349.23));
@ print(cal(392));
@ print(cal(415.30));


@ 81.72716747258734
@ 68.72261833175844
@ 61.22448979591836
@ 57.78954972309174