Files
open-roms/c64/kernal/tape/tape_turbo_get_bit.s
T

36 lines
752 B
ArmAsm

// #LAYOUT# STD * #TAKE
// #LAYOUT# * KERNAL_0 #TAKE
// #LAYOUT# * * #IGNORE
//
// Tape (turbo) helper routine - bit reading
//
// Based on routine by enthusi/Onslaught, found here:
// - https://codebase64.pokefinder.org/doku.php?id=base:turbotape_loader_source
#if CONFIG_TAPE_TURBO
tape_turbo_get_bit:
#if CONFIG_TAPE_NORMAL
jsr tape_normal_get_pulse // reuse routine from NORMAL system
#else
lda #$10
!:
bit CIA1_ICR // $DC0D
beq !- // busy loop to detect signal, restart timer afterwards
lda CIA2_TIMBLO // $DD06
ldx #%01010001 // start timer, force latch reload, count timer A underflows
stx CIA2_CRB // $DD0F
#endif
#endif // CONFIG_TAPE_TURBO