;;
;; Kitsune's Curse
;; Copyright (C) 2020-2023 Juan J. Martinez <jjm@usebox.net>
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
;;
;;
;; TAPE LOADER
;;

.include "cpcfirm.inc"
.include "../build/loader.opt"

loader:

.ifeq DISK
	; loading from disk

	ld hl, (#0xbe7d)	; save current drive
	ld a, (hl)
	ld (#drive+1), a
.endif ; end disk code

	ld c, #0xff
	ld hl, #start
	call mc_start_program

start:
	call kl_rom_walk

.ifeq DISK
drive:
	ld a, #0		; restore drive
	ld hl, (#0xbe7d)
	ld (hl), a
.endif ; end disk code

	ld bc, #0		; set border
	call scr_set_border

	ld bc, #0		; bg color
	xor a
	call scr_set_ink

	xor a			; set mode 0
	call scr_set_mode

	ld a, #0xff
	call cas_noisy ; disable tape texts

.ifeq DISK
					; first file is the SCRX
	call load_file

.else ; tape code

	ld ix, #TMP_ADDR
	ld de, #SCRX_SIZE
	call turboload

.endif ; end tape code

					; setup the palette
	ld hl, #TMP_ADDR + #4
	call set_palette

	; border is already 0

	ld hl, #TMP_ADDR + #0x14 ; compressed data
	ld de, #0xc000	; uncompress into the screen
	call aplib_depack

	; loader size limited to 1024 bytes!
LOADER_END = LOADER_ADDR + 1024

.ifeq DISK

	ld hl, #fname_end - #1
	inc (hl)
					; load the code
	call load_file

.else ; tape code

	; change stripes
	ld a, #20
	ld (#turbo_col + 1), a

	; load the compressed app
	ld ix, #LOADER_END
	ld de, #APP_SIZE_PAK
	call turboload

.endif ; tape code ends

	di
	; disable the firmware
	im 1
	ld hl, #0x38
	ld (hl), #0xfb
	inc hl
	ld (hl), #0xc9

	; put the stack as high as we can
	ld sp, #0xc000
	ei

	; disable upper/lower roms
	ld bc, #0x7f8c
	out (c), c

	; relocate the compressed data
	ld bc, #APP_SIZE_PAK
	ld hl, #LOADER_END + #APP_SIZE_PAK
	ld de, #LOADER_END + #APP_SIZE + #PAK_SLOP
data_relocation_loop:
	ld a, (hl)
	ld (de), a
	dec hl
	dec de
	ld a, b
	or c
	dec bc
	jr nz, data_relocation_loop

	; uncompress after the loader
	ld hl, #LOADER_END + #APP_SIZE - (#APP_SIZE_PAK - #PAK_SLOP)
	ld de, #LOADER_END
	call aplib_depack

	; relocate app to its final address
	ld bc, #APP_SIZE
	ld hl, #LOADER_END + #APP_SIZE
	ld de, #APP_ADDR + #APP_SIZE
relocation_loop:
	ld a, (hl)
	ld (de), a
	dec hl
	dec de
	ld a, b
	or c
	dec bc
	jr nz, relocation_loop

	; jp to the app entry point
	.db #0xc3
	.dw #APP_EP

set_palette:
	push hl
	call wait_vsync

	halt
	halt

	call wait_vsync
	pop hl

	xor a
set_palette_loop:
	push hl
	push af
	ld c, (hl)
	ld b, c
	call scr_set_ink
	pop af
	pop hl
	inc hl
	inc a
	cp #0x10
	jr nz, set_palette_loop

	halt
	halt
	halt
	halt
	halt
	halt
	ret

wait_vsync:
	ld b, #0xf5
	keep_waiting:
	in a, (c)
	rra
	jr nc, keep_waiting
	ret

.ifeq DISK

load_file:
	ld hl, #fname
	ld b, #fname_end-#fname

	ld de, #0x400		; temp mem (only used in tape mode)
	call cas_in_open

	push de
	pop hl
	call cas_in_direct

	call cas_in_close
	ret

fname:
	.str "MAIN.BI0"
fname_end:

.else ; tape code

turboload:
	di
	ex af, af'
	push af
	ex af, af'
	exx
	push de
	push bc
	push hl
	exx
	xor a
	ld r, a
	dec a
	call _turboload
	jp nc, 0
	exx
	pop hl
	pop bc
	pop de
	exx
	ex af, af'
	pop af
	ex af, af'
	ei
	ret

.include "turboload.s"
.endif ; end tape code

.area _DATA