pinky/nes-testsuite/roms/sprite_overflow_tests/source/3.Timing.a

; Tests sprite overflow flag timing

     .include "prefix.a"

test_name:
     .db  "SPRITE OVERFLOW TIMING",0
     .code

begin_timing:
     sta  result
     jsr  sync_ppu_20
     lda  #$18
     sta  $2001
     jsr  dma_sprite_table
     pha  ; 14 delay for later expansion
     pla
     pha
     pla
     rts
     
check_sprite_overflow_timing:
     txa
     and  #$20
     jsr  error_if_ne
     inc  result
     tya
     and  #$20
     jsr  error_if_eq
     rts

reset:
     jsr  begin_sprite_overflow_tests
     
     lda  #128
     ldx  #0
     ldy  #9
     jsr  move_sprites
     lda  #2;) Cleared too late/3)too early at end of VBL
     jsr  begin_timing
     ldy  #61       ; 31497 delay
     lda  #102      
     jsr  delay_ya4
     ldy  $2002
     ldx  $2002
     jsr  check_sprite_overflow_timing
     
     jsr  clear_sprite_table
     lda  #0
     ldx  #0
     ldy  #9
     jsr  move_sprites
     lda  #0
     ldx  #3
     ldy  #9
     jsr  move_sprites
     lda  #4;) Set too early/5)too late for first scanline
     jsr  begin_timing
     ldy  #2        ; 1874 delay (1873 and 1875 work reliably,
     lda  #184      ; 1872 and 1876 fail part of the time)
     jsr  delay_ya5
     ldx  $2002
     ldy  $2002
     jsr  check_sprite_overflow_timing
     
     lda  #255
     ldx  #3
     ldy  #9
     jsr  move_sprites
     lda  #6;) Sprite horizontal positions should have no effect on timing
     jsr  begin_timing
     ldy  #2        ; 1874 delay (1873 and 1875 work reliably,
     lda  #184      ; 1872 and 1876 fail part of the time)
     jsr  delay_ya5
     lda  $2002
     ldx  $2002
     and  #$20
     jsr  error_if_ne
     txa
     and  #$20
     jsr  error_if_eq
     
     jsr  clear_sprite_table
     lda  #0
     ldx  #220
     ldy  #9
     jsr  move_sprites
     lda  #7;) Set too early/ 8)late for last sprites on first scanline
     jsr  begin_timing
     ldy  #8        ; 1911 delay (1909 fails often and 1912 fails occasionally)
     lda  #46       
     jsr  delay_ya6
     ldx  $2002
     ldy  $2002
     jsr  check_sprite_overflow_timing

     jsr  clear_sprite_table
     lda  #239
     ldx  #0
     ldy  #9
     jsr  move_sprites
     lda  #9;) Set too early/10)too late for last scanline
     jsr  begin_timing
     ldy  #26       ; 29040 delay (29038 and 29042 fail sometimes)
     lda  #222      
     jsr  delay_ya7
     ldx  $2002
     ldy  $2002
     jsr  check_sprite_overflow_timing
     
     jsr  clear_sprite_table
     lda  #0
     ldx  #0
     ldy  #8
     jsr  move_sprites
     lda  #0
     sta  sprites + 255
     lda  #11;) Set too early/12)too late when 9th sprite # is way after 8th
     jsr  begin_timing
     ldy  #8        ; 1911 delay (1909 fails often and 1912 fails occasionally)
     lda  #46       
     jsr  delay_ya6
     ldx  $2002
     ldy  $2002
     jsr  check_sprite_overflow_timing
     
     jsr  clear_sprite_table
     lda  #0
     ldx  #4
     ldy  #8
     jsr  move_sprites
     lda  #1
     sta  sprites + 0
     lda  #13;) Overflow on second scanline occurs too early/14)too late
     jsr  begin_timing
     ldy  #3        ; 1987 delay (1986 & 1988 work too)
     lda  #130      
     jsr  delay_ya2
     ldx  $2002
     ldy  $2002
     jsr  check_sprite_overflow_timing
     
     jmp  tests_passed