//
// DolphinDOS protocol support for IEC - optimized load loop
//


#if CONFIG_IEC_DOLPHINDOS && !CONFIG_MEMORY_MODEL_60K


dolphindos_load:

	// Timing is critical for some parts, do not allow interrupts
	sei

	// A trick to shorten EAL update time
	ldy #$00

#if CONFIG_IEC_DOLPHINDOS_FAST
	// Another trick: prepare values for quickly setting/releasing DATA
	lda CIA2_PRA
	and #$FF - BIT_CIA2_PRA_DAT_OUT - BIT_CIA2_PRA_CLK_OUT - BIT_CIA2_PRA_ATN_OUT
	sta IECPROTO                       // release DATA
	ora #BIT_CIA2_PRA_DAT_OUT
	sta TBTCNT                         // pull DATA
#endif

	// FALLTROUGH

dolphindos_load_loop:

#if !CONFIG_IEC_DOLPHINDOS_FAST
	// Check if this was EOI
	bit IOSTATUS
	bvs dolphindos_load_end
#endif

	// Wait for the talker to release the CLK line
!:
	bit CIA2_PRA
	bvc !-

	// Release the DATA to signal we are ready
#if !CONFIG_IEC_DOLPHINDOS_FAST
	lda CIA2_PRA
	and #$FF - BIT_CIA2_PRA_DAT_OUT    // release
#else
	lda IECPROTO
#endif
	sta CIA2_PRA

#if !CONFIG_IEC_DOLPHINDOS_FAST

	// Check if EOI
	jsr iec_rx_check_eoi               // can damage .X, but this is safe

#else

	// Check if EOI - inlined code to avoid wasting cycles on RTS
	ldx #$13
!:
	bit CIA2_PRA
	bvc dolphindos_load_no_eoi
	dex
    bne !-  

    // EOI - mark it and retrieve the last byte
    jsr iec_rx_check_eoi_confirm
	lda CIA2_PRB
	sta (EAL),y

	// Update EAL for the last time
	sec
	jsr iec_update_EAL_by_Y

	// Restore proper IECPROTO value
	lda #$02
	sta IECPROTO

	// End of load loop
	jmp load_iec_loop_end

dolphindos_load_no_eoi:

#endif

	// Retrieve and store byte
	lda CIA2_PRB
	sta (EAL),y

	// Pull DATA to acknowledge
#if !CONFIG_IEC_DOLPHINDOS_FAST
	lda CIA2_PRA
	ora #BIT_CIA2_PRA_DAT_OUT
#else
	lda TBTCNT
#endif
	sta CIA2_PRA

	// Handle EAL
	iny
	bne dolphindos_load_loop
	inc EAL+1
	jmp dolphindos_load_loop

#if !CONFIG_IEC_DOLPHINDOS_FAST

dolphindos_load_end:

	// Update EAL
	clc
	jsr iec_update_EAL_by_Y

	// End of load loop
	jmp load_iec_loop_end

#endif


#endif // CONFIG_IEC_DOLPHINDOS and not CONFIG_MEMORY_MODEL_60K