path: root/src/splib.c

/*
   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/>.
 */
#include <stdlib.h>
#include <string.h>

#include "splib.h"
#include "font.h"

//#define SPRITE_DEBUG
//#define FENCE_DEBUG

struct st_tile tiles[TMW * TMH];
struct st_tile *dirty;
uint8_t *mini_buffer;

// faster
struct st_tile *tile_p;

#ifdef FENCE_DEBUG
// (sprite th * 2 + 2) * msx sprites
#define MAX_MINI_BUFFER (3 * 2 + 2) * 10
uint8_t mini_buffer_cnt;
#endif

void pad_numbers(uint8_t *s, uint8_t limit, uint16_t number)
{
    s += limit;
    *s = 0;

    do
    {
        limit--;
        *--s = (number % 10) + '0';
        number /= 10;
    } while (limit);
}

#pragma save
#pragma disable_warning 85
void set_hw_border(uint8_t c) __z88dk_fastcall
{
    // *INDENT-OFF*
    __asm;
	ld bc, #0x7f10
	out (c), c
	ld c, l
	out (c), c
    __endasm;
    // *INDENT-ON*
}
#pragma restore

#pragma save
#pragma disable_warning 85
void set_hw_ink(uint8_t ink, uint8_t c)
{
    // *INDENT-OFF*
    __asm;
	ld hl, #2
	add hl, sp
	ld a, (hl)
	inc hl
	ld e, (hl)
	ld bc, #0x7f00
	out (c), a
	ld a, #0x40
	or e
	out (c), a
    __endasm;
    // *INDENT-ON*
}
#pragma restore

void wait_vsync()
{
    // *INDENT-OFF*
    __asm;
	ld b, #0xf5
keep_waiting:
	in a, (c)
	rra
	jr nc, keep_waiting
    __endasm;
    // *INDENT-ON*
}

void clear_screen()
{
    memset((uint8_t*)0xc000, 0, 16383);
}

// this is quite slow, use it only where speed is not an issue
uint16_t screen_addr(uint16_t x, uint16_t y)
{
    // up to 160 x 200
    return (0xc000 + x + ((y / 8) * 80) + ((y % 8) * 2048));
}

void init_tiles()
{
    uint8_t i, j;

    memset(tiles, 0, sizeof(struct st_tile) * TMW * TMH);

    for (j = 0; j < TMH; ++j)
        for (i = 0; i < TMW; ++i)
            tiles[i + j * TMW].saddr = screen_addr((uint16_t)i * TW / 2, 32 + (uint16_t)j * TH);

    dirty = NULL;
    mini_buffer = (uint8_t *)BUFF_ADDR;

#ifdef FENCE_DEBUG
    mini_buffer_cnt = 0;
#endif
}

void update_screen()
{
    // tiles are expected to be 8x8 pixels
    // *INDENT-OFF*
    __asm;
	call _wait_int6

	ld hl, (_dirty)

update_loop:
	ld a, h
	or l
	jr z, update_done

	; baddr in de; and reset it
	xor a
	ld e, (hl)
	ld (hl), a
	inc hl
	ld d, (hl)
	ld (hl), a
	inc hl

	; clean dirty flag
	res 7, d
	ld a, d
	or e
	jr nz, linked_buffer

	; not linked, use the original tile
	; hl has *t
	ld e, (hl)
	inc hl
	ld d, (hl)
	dec hl

linked_buffer:
	; skip *t
	inc hl
	inc hl

	; saddr in a, c
	ld c, (hl)
	inc hl
	ld a, (hl)
	inc hl

	; pointing to next
	push hl

	; baddr in hl
	ex de, hl
	; saddr to de
	ld e, c
	ld d, a

	ld a, #8
put_tile0:
	ldi
	ldi
	ldi
	ldi

	dec a
	jp z, put_tile2

	; inc destination
	ex de, hl
	ld bc, #0x07fc
	add hl, bc
	jp nc, put_tile1
	ld bc, #0xc048
	add hl, bc
put_tile1:
	ex de, hl
	jr put_tile0

put_tile2:
	; next dirty tile
	pop hl
	ld a, (hl)
	inc hl
	ld h, (hl)
	ld l, a

	jp update_loop

update_done:

	; a is 0
	ld (_dirty), a
	ld (_dirty + #1), a

#ifdef FENCE_DEBUG
        ld (_mini_buffer_cnt), a
#endif

	; reset mini buffers (begin buffer at 0x0100)
	ld (_mini_buffer), a
	inc a
	ld (_mini_buffer + #1), a
    __endasm;
    // *INDENT-ON*
}

void validate_screen()
{
    for (; dirty; dirty = dirty->n)
        dirty->baddr = 0;

    // dirty is NULL
    mini_buffer = (uint8_t *)BUFF_ADDR;
}

void invalidate_screen()
{
    uint16_t i;

    dirty = NULL;
    mini_buffer = (uint8_t *)BUFF_ADDR;

    for (i = TMW * TMH; i; i--)
    {
        tiles[i - 1].baddr &= ADDR_BITS;
        invalidate_tile(&tiles[i - 1]);
    }
}

void invalidate_tile(struct st_tile *st) __z88dk_fastcall
{
    /*
    if (st->baddr & DIRTY_BIT)
    	return;

    st->baddr |= DIRTY_BIT;
    st->n = dirty;
    dirty = st;
    */
    // *INDENT-OFF*
    __asm;
	ld e, l
	ld d, h

	; test for dirty bit
	inc hl
	ld a, (hl)
	bit #7, a
	ret nz

	; set dirty bit
	set #7, a
	ld (hl), a

	; set *n to dirty
	ld a, #5
	add a, l
	ld l, a
	adc a, h
	sub l
	ld h, a

	ld a, (#_dirty)
	ld (hl), a
	inc hl
	ld a, (#_dirty + #1)
	ld (hl), a

	; set dirty to *st
	ld (_dirty), de
    __endasm;
    // *INDENT-ON*
}

struct st_tile *get_tile_xy(uint8_t x, uint8_t y)
{
    // x and y in tilemap coordinates

#ifdef FENCE_DEBUG
    if (x > TMW || y > TMH)
        set_hw_border(0x4b);
#endif

    return &tiles[x + (uint16_t)y * TMW];
}

#pragma save
#pragma disable_warning 59
uint8_t is_invalid_tile(struct st_tile *st) __z88dk_fastcall
{
    // *INDENT-OFF*
    __asm;
	inc hl
	ld a, (hl)
	and #128
	ld l, a
    __endasm;
    // *INDENT-ON*
}
#pragma restore

#pragma save
#pragma disable_warning 59
uint8_t is_invalid_tile2(struct st_tile *st) __z88dk_fastcall
{
    // *INDENT-OFF*
    __asm;
	inc hl
	ld a, (hl)
	and #128
	jr nz, is_invalid
	ld bc, #(TMW * 8)
	add hl, bc
	ld a, (hl)
	and #128
is_invalid:
	ld l, a
    __endasm;
    // *INDENT-ON*
}
#pragma restore

void erase_tile(struct st_tile *st) __z88dk_fastcall
{
    // *INDENT-OFF*
    __asm;
	; if it has a linked buffer, it was erased already
	; testing MSB only
	inc hl
	ld a, (hl)
	or a
	ret nz

	dec hl

	; and if there is no linked buffer, it is not invalidated

	; set dirty bit (if not set already)
	jp _invalidate_tile
    __endasm;
    // *INDENT-ON*
}

void link_buffer(struct st_tile *st) __z88dk_fastcall
{
    // *INDENT-OFF*
    __asm;
	; check is not linked already
	; testing MSB only
	inc hl
	ld a, (hl)
	and #127
	ret nz

	dec hl

#ifdef FENCE_DEBUG
        ld a, (_mini_buffer_cnt)
        inc a
        ld (_mini_buffer_cnt), a

        cp #MAX_MINI_BUFFER
        jp c, mini_buffers_ok

	ld hl, #0x58
	jp _set_hw_border

mini_buffers_ok:
#endif

	; save *st
	push hl

	; allocate a new buffer
	ex de, hl
	ld hl, (_mini_buffer)
	ld c, l
	ld b, h
	ex de, hl

	; new buffer to baddr, preserve dirty bit
	ld (hl), c
	inc hl
	ld a, (hl)
	and #128
	or b
	ld (hl), a
	dec hl

	; move mini buffer pointer
	ex de, hl
	ld hl, #(TW * TH / 2)
	add hl, bc
	ld (_mini_buffer), hl
	ex de, hl

	; baddr to de
	ld e, c
	ld d, b

	; *t to hl
	inc hl
	inc hl
	ld a, (hl)
	inc hl
	ld h, (hl)
	ld l, a

#ifdef SPRITE_DEBUG
	ld hl, #_bgtiles + 14 * 32
#endif

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	ldi
	ldi
	ldi
	ldi

	; *st
	pop hl
	jp _invalidate_tile
    __endasm;
    // *INDENT-ON*
}

void put_tile(const uint8_t *t, struct st_tile *st)
{
    st->t = t;
    invalidate_tile(st);
}

#pragma save
#pragma disable_warning 85
void erase_sprite(uint8_t x, uint8_t y, uint8_t th)
{
    // for 8 pixels wide sprites, th in tiles
    // *INDENT-OFF*
    __asm;
	ld hl, #2
	add hl, sp
	ld c, (hl) ; x
	inc hl
	ld e, (hl) ; y
	inc hl
	ld b, (hl) ; th

	ld a, e

	; out of bounds check
	cp #(TMH * TH - 8)
	jr nc, no_inc_th

	and #0x07
	jr z, no_inc_th
	inc b

no_inc_th:
	ld l, c ; x
	srl l
	srl l
	srl l

	ld a, e ; y
	srl a
	srl a
	srl a
	add a, b ; add th
	ld h, a

	push bc
	push hl
	call _get_tile_xy
	pop af
	pop bc
	; hl has the tile addr

	.db 0xdd
	ld l, b

	ld a, c
	and #0x07
	jr z, erase_tile_loop_no_extra_x

erase_tile_loop:
	xor a
	ld de, #(TMW * 8)
	sbc hl, de
	; dec tile ptr 1 row as th decrements

	push hl
	call _erase_tile
	pop hl

	push hl
	ld de, #8
	add hl, de
	; tile ptr + 1
	call _erase_tile
	pop hl

	.db 0xdd
	dec l
	jr nz, erase_tile_loop
	ret

erase_tile_loop_no_extra_x:
	xor a
	ld de, #(TMW * 8)
	sbc hl, de
	; dec tile ptr 1 row as th decrements

	push hl
	call _erase_tile
	pop hl

	.db 0xdd
	dec l
	jr nz, erase_tile_loop_no_extra_x

    __endasm;
    // *INDENT-ON*
}
#pragma restore

const uint8_t inv_table[] = {
    0, 2, 1, 3, 8, 10, 9, 11, 4, 6, 5, 7, 12, 14, 13, 15, 32, 34, 33, 35, 40,
    42, 41, 43, 36, 38, 37, 39, 44, 46, 45, 47, 16, 18, 17, 19, 24, 26, 25, 27,
    20, 22, 21, 23, 28, 30, 29, 31, 48, 50, 49, 51, 56, 58, 57, 59, 52, 54, 53,
    55, 60, 62, 61, 63, 128, 130, 129, 131, 136, 138, 137, 139, 132, 134, 133,
    135, 140, 142, 141, 143, 160, 162, 161, 163, 168, 170, 169, 171, 164, 166,
    165, 167, 172, 174, 173, 175, 144, 146, 145, 147, 152, 154, 153, 155, 148,
    150, 149, 151, 156, 158, 157, 159, 176, 178, 177, 179, 184, 186, 185, 187,
    180, 182, 181, 183, 188, 190, 189, 191, 64, 66, 65, 67, 72, 74, 73, 75, 68,
    70, 69, 71, 76, 78, 77, 79, 96, 98, 97, 99, 104, 106, 105, 107, 100, 102,
    101, 103, 108, 110, 109, 111, 80, 82, 81, 83, 88, 90, 89, 91, 84, 86, 85,
    87, 92, 94, 93, 95, 112, 114, 113, 115, 120, 122, 121, 123, 116, 118, 117,
    119, 124, 126, 125, 127, 192, 194, 193, 195, 200, 202, 201, 203, 196, 198,
    197, 199, 204, 206, 205, 207, 224, 226, 225, 227, 232, 234, 233, 235, 228,
    230, 229, 231, 236, 238, 237, 239, 208, 210, 209, 211, 216, 218, 217, 219,
    212, 214, 213, 215, 220, 222, 221, 223, 240, 242, 241, 243, 248, 250, 249,
    251, 244, 246, 245, 247, 252, 254, 253, 255
};

#pragma save
#pragma disable_warning 85
void put_sprite_rc_nm(uint8_t *d, uint8_t dox, uint8_t doy, uint8_t w, uint8_t h, const uint8_t *s, uint8_t sox, uint8_t soy)
{
    // x offset must be even

    /*
    uint8_t i, j;

    d += dox + doy * TW / 2;
    s += sox + soy * TW / 2;

    for (j = 0; j < h; j++)
    {
    	for (i = 0; i < w; i++)
    		*d++ = *s++;

    	s += (TW / 2) - w;
    	d += (TW / 2) - w;
    }

    */
    // *INDENT-OFF*
    __asm;

	ld hl, #2
	add hl, sp
	ld e, (hl)
	inc hl
	ld d, (hl)
	inc hl
	; de has *d

	ld b, #0
	ld c, (hl)
	; bc has dox
	inc hl
	ld a, (hl)
	sla a
	sla a
	ex de, hl
	; add dox
	add hl, bc
	ld c, a
	; bc has doy * TW / 2
	add hl, bc
	ex de, hl

	; d* is ready
	push de

	inc hl
	inc hl
	inc hl
	ld e, (hl)
	inc hl
	ld d, (hl)
	inc hl
	; de has *s

	; b is 0
	ld c, (hl)
	; bc has sox
	inc hl
	ld a, (hl)
	sla a
	sla a
	; a has soy * TW / 2
	ex de, hl
	; add sox
	add hl, bc
	ld c, a
	; add soy * TW / 2
	add hl, bc
	ex de, hl

	ld hl, #(6 + 2)
	add hl, sp
	ld c, (hl)
	inc hl
	; c is w

	; the reminder
	ld a, #4
	sub c
	ld (no_inv_sub_w_nm + 1), a

	; and build jump addr
	sla a
	ld (no_inv_inner_w_nm + 1), a


	ld a, (hl)
	; h

	; hl has *s
	ex de, hl

	; *d
	pop de

	ld b, #0
no_inv_height_nm:

no_inv_inner_w_nm:
	jr no_inv_inner_w_nm

	ldi
	ldi
	ldi
	ldi

	; b is 0

	; inc *d
no_inv_sub_w_nm:
	ld c, #0

	ex de, hl
	add hl, bc
	ex de, hl

	; inc *s
	add hl, bc

	dec a
	jr nz, no_inv_height_nm

    __endasm;
    // *INDENT-ON*
}
#pragma restore

#pragma save
#pragma disable_warning 85
void put_sprite_rc(uint8_t *d, uint8_t dox, uint8_t doy, uint8_t w, uint8_t h, const uint8_t *s, uint8_t sox, uint8_t soy, uint8_t inv)
{
    /*
    uint8_t i, j;

    d += dox + doy * TW / 2;

    if (inv)
    	s += TW - 2 * (1 + sox) + soy * TW;
    else
    	s += 2 * sox + soy * TW;

    if (inv)
    {
    	for (j = 0; j < h; j++)
    	{
    		for (i = 0; i < w; i++)
    		{
    			*d &= inv_table[*s++];
    			*d++ |= inv_table[*s];
    			s -= 3;
    		}
    		s += (TW / 2 + w) * 2;
    		d += TW / 2 - w;
    	}
    }
    else
    {
    	for (j = 0; j < h; j++)
    	{
    		for (i = 0; i < w; i++)
    		{
    			*d &= *s++;
    			*d++ |= *s++;
    		}
    		s += (TW / 2 - w) * 2;
    		d += TW / 2 - w;
    	}
    }
    */
    // *INDENT-OFF*
    __asm;

	ld hl, #2
	add hl, sp
	ld e, (hl)
	inc hl
	ld d, (hl)
	inc hl
	; de has *d

	ld b, #0
	ld c, (hl)
	; bc has dox
	inc hl
	ld a, (hl)
	sla a
	sla a
	ex de, hl
	add hl, bc
	ld c, a
	; bc has doy * TW / 2
	add hl, bc
	ex de, hl

	; d* is ready
	push de

	inc hl
	inc hl
	inc hl
	ld e, (hl)
	inc hl
	ld d, (hl)
	inc hl
	; de has *s

	; b is 0
	inc hl
	ld c, (hl)
	sla c
	sla c
	sla c
	; bc has soy
	ex de, hl
	add hl, bc
	ex de, hl

	; common *s part is ready
	inc hl
	ld a, (hl)
	or a
	jr z, setup_no_inv

	; blit inv

	ld hl, #(10 + 2)
	add hl, sp

	; b is 0
	ld c, (hl)
	inc c
	sla c
	xor a
	sub a, c
	ld c, a
	ld a, #0
	sbc b
	ld b, a
	; bc has - 2 - 2 x sox
	ex de, hl
	add hl, bc
	ld bc, #8
	; add TW
	add hl, bc
	ex de, hl

	; de has *s ready for inv

	ld hl, #(6 + 2)
	add hl, sp

	ld a, (hl)
	; w

	; set this in the code
	ld (inv_inner_w + 1), a

	ld b, a
	ld a, #4
	sub b
	ld (inv_sub_w + 1), a

	ld a, #4
	add b
	sla a
	ld (inv_add_w + 1), a

	inc hl

	ld a, (hl)

	; *d
	pop hl
	ex de, hl

	push ix
	.db 0xdd
	ld h, a
	; h

inv_height:

	.db 0xdd
inv_inner_w:
	ld l, #0

inv_width:

	; add 8-bit number to a 16-bit reg
	;
	; add a, l
	; ld l, a
	; adc a, h
	; sub l
	; ld h, a

	; first flip bg
	ld a, (de)

	ld bc, #_inv_table
	add a, c
	ld c, a
	adc a, b
	sub c
	ld b, a

	ld a, (bc)

	; and mask; or sprite
	and (hl)
	inc hl
	or (hl)

	; flip again

	ld bc, #_inv_table
	add a, c
	ld c, a
	adc a, b
	sub c
	ld b, a

	ld a, (bc)

	ld (de), a
	inc de

	dec hl
	dec hl
	dec hl

	.db 0xdd
	dec l
	jr nz, inv_width

	; inc *s
inv_add_w:
	ld a, #0
	add a, l
	ld l, a
	adc a, h
	sub l
	ld h, a

	; inc *d
inv_sub_w:
	ld a, #0
	add a, e
	ld e, a
	adc a, d
	sub e
	ld d, a

	.db 0xdd
	dec h
	jr nz, inv_height

	pop ix

	ret

setup_no_inv:

	ld hl, #(10 + 2)
	add hl, sp

	; b is 0
	ld c, (hl)
	sla c
	ex de, hl
	add hl, bc
	; add 2 x sox to *s
	ex de, hl

	ld hl, #(6 + 2)
	add hl, sp
	ld a, (hl)
	inc hl
	; w
	ld (no_inv_inner_w + 1), a

	ld b, a
	ld a, #4
	sub b
	ld (no_inv_sub_w + 1), a
	sla a
	ld (no_inv_sub_w2 + 1), a

	ld c, (hl)
	; h

	; hl has *s
	ex de, hl

	; *d
	pop de

no_inv_height:

no_inv_inner_w:
	ld b, #0

no_inv_width:

	; and mask; or sprite
	ld a, (de)
	and (hl)
	inc hl
	or (hl)
	inc hl
	ld (de), a
	inc de

	djnz no_inv_width

	; inc *d
no_inv_sub_w:
	ld a, #0
	add a, e
	ld e, a
	adc a, d
	sub e
	ld d, a

	; inc *s (x2)
no_inv_sub_w2:
	ld a, #0
	add a, l
	ld l, a
	adc a, h
	sub l
	ld h, a

	dec c
	jr nz, no_inv_height

    __endasm;
    // *INDENT-ON*
}
#pragma restore

void put_sprite4(const uint8_t *s, uint8_t x, uint8_t y, uint8_t th, uint8_t inv)
{
    /*
    uint8_t xoffs, yoffs;

    xoffs = (x % TW) / 2;
    yoffs = y % TH;

    tile_p = get_tile_xy(x >> 3, (y >> 3));

    // top
    link_buffer(tile_p);
    put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), xoffs, yoffs, TW / 2 - xoffs, TH - yoffs, s, 0, 0, inv);
    if (xoffs)
    {
    	tile_p++;
    	link_buffer(tile_p);
    	put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), 0, yoffs, xoffs, TH - yoffs, s, TW / 2 - xoffs, 0, inv);
    }

    if (th > 1)
    {
    	// center 1
    	tile_p = get_tile_xy(x >> 3, (y >> 3) + 1);

    	link_buffer(tile_p);
    	put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), xoffs, 0, TW / 2 - xoffs, TH, s, 0, TH - yoffs, inv);
    	if (xoffs)
    	{
    		tile_p++;
    		link_buffer(tile_p);
    		put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), 0, 0, xoffs, TH, s, TW / 2 - xoffs, TH - yoffs, inv);
    	}

    	if (th > 2)
    	{
    		// center 2
    		tile_p = get_tile_xy(x >> 3, (y >> 3) + 2);

    		link_buffer(tile_p);
    		put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), xoffs, 0, TW / 2 - xoffs, TH, s, 0, 2 * TH - yoffs, inv);
    		if (xoffs)
    		{
    			tile_p++;
    			link_buffer(tile_p);
    			put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), 0, 0, xoffs, TH, s, TW / 2 - xoffs, 2 * TH - yoffs, inv);
    		}

    		// reminder
    		if (yoffs) {
    			tile_p = get_tile_xy(x >> 3, (y >> 3) + 3);

    			link_buffer(tile_p);
    			put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), xoffs, 0, TW / 2 - xoffs, yoffs, s, 0, 3 * TH - yoffs, inv);
    			if (xoffs)
    			{
    				tile_p++;
    				link_buffer(tile_p);
    				put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), 0, 0, xoffs, yoffs, s, TW / 2 - xoffs, 3 * TH - yoffs, inv);
    			}
    		}
    	}
    	else
    	{
    		// reminder
    		if (yoffs) {
    			tile_p = get_tile_xy(x >> 3, (y >> 3) + 2);

    			link_buffer(tile_p);
    			put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), xoffs, 0, TW / 2 - xoffs, yoffs, s, 0, 2 * TH - yoffs, inv);
    			if (xoffs)
    			{
    				tile_p++;
    				link_buffer(tile_p);
    				put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), 0, 0, xoffs, yoffs, s, TW / 2 - xoffs, 2 * TH - yoffs, inv);
    			}
    		}
    	}
    }
    else
    {
    	// reminder
    	if (yoffs) {
    		tile_p = get_tile_xy(x >> 3, (y >> 3) + 1);

    		link_buffer(tile_p);
    		put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), xoffs, 0, TW / 2 - xoffs, yoffs, s, 0, TH - yoffs, inv);
    		if (xoffs)
    		{
    			tile_p++;
    			link_buffer(tile_p);
    			put_sprite_rc((uint8_t *)(tile_p->baddr & ADDR_BITS), 0, 0, xoffs, yoffs, s, TW / 2 - xoffs, TH - yoffs, inv);
    		}
    	}
    }
    */

    // *INDENT-OFF*
    __asm;

	; for xoffs and yoffs
	push af

	ld ix, #0
	add ix, sp

	ld a, 2 + 4 (ix)
	and #7
	srl a
	ld 0 (ix), a
	; (x mod 8) / 2 -> xoffs

	ld a, 3 + 4 (ix)
	and #7
	ld 1 (ix), a
	; (y mod 8) -> yoffs

	ld e, 2 + 4 (ix)
	srl e
	srl e
	srl e
	ld d, 3 + 4 (ix)
	srl d
	srl d
	srl d
	push de
	; x >> 3, y >> 3
	call _get_tile_xy
	pop af

	; *tile
	push hl
	; fastcall, does not use ix
	call _link_buffer
	pop hl
	push hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	ld b, 5 + 4 (ix)
	; inv
	ld c, #0
	push bc
	; soy
	ld b, #0
	push bc
	inc sp
	; soy
	ld c, 0 + 4 (ix)
	ld b, 1 + 4 (ix)
	push bc
	; *s
	; xoffs & yoffs are on the stack
	ld a, #4
	sub 0 (ix)
	ld c, a
	ld a, #8
	sub 1 (ix)
	ld b, a
	push bc
	; TH / 2 - xoffs, TH - yoffs
	ld c, 0 (ix)
	ld b, 1 (ix)
	push bc
	; xoffs, yoffs
	push de
	; baddr
	call _put_sprite_rc

	ld iy, #0
	add iy, sp

	ld a, 0 (ix)
	or a
	jr z, put_sprite4_xaligned0

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #8
	add hl, bc
	; *tile + 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters that changed
	xor a
	ld 2 (iy), a
	; 0

	ld c, 4 (iy)
	; TW / 2 - xoffs

	ld a, 0 (ix)
	ld 4 (iy), a
	; xoffs

	ld 8 (iy), c
	; TW / 2 - xoffs

	call _put_sprite_rc

put_sprite4_xaligned0:

	ld a, 4 + 4 (ix)
	cp #1
	jp z, put_sprite4_reminder_th1

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * 20)
	add hl, bc
	; *tile + TMW

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters
	ld a, 0 (ix)
	ld 2 (iy), a
	; xoffs

	xor a
	ld 3 (iy), a
	ld 8 (iy), a
	; 0

	ld a, #4
	sub 0 (ix)
	ld 4 (iy), a
	; TW / 2 - xoffs

	ld a, #8
	ld 5 (iy), a
	; TH

	; a is 8
	sub 1 (ix)
	ld 9 (iy), a
	; TH  - yoffs

	call _put_sprite_rc

	ld a, 0 (ix)
	or a
	jr z, put_sprite4_xaligned1

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * (20 + 1))
	add hl, bc
	; *tile + TMW + 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters that changed
	xor a
	ld 2 (iy), a
	; 0

	ld c, 4 (iy)
	; TW / 2 - xoffs

	ld a, 0 (ix)
	ld 4 (iy), a
	; xoffs

	ld 8 (iy), c
	; TW / 2 - xoffs

	call _put_sprite_rc

put_sprite4_xaligned1:

	ld a, 4 + 4 (ix)
	cp #2
	jp z, put_sprite4_reminder_th2

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * 20 * 2)
	add hl, bc
	; *tile + TMW * 2

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters
	ld a, 0 (ix)
	ld 2 (iy), a
	; xoffs

	xor a
	ld 3 (iy), a
	ld 8 (iy), a
	; 0

	ld a, #4
	sub 0 (ix)
	ld 4 (iy), a
	; TW / 2 - xoffs

	ld a, #8
	ld 5 (iy), a
	; TH

	sla a
	; TH * 2
	sub 1 (ix)
	ld 9 (iy), a
	; 2 * TH  - yoffs

	call _put_sprite_rc

	ld a, 0 (ix)
	or a
	jr z, put_sprite4_reminder

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * (20 * 2 + 1))
	add hl, bc
	; *tile + 2 * TMW + 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters that changed
	xor a
	ld 2 (iy), a
	; 0

	ld c, 4 (iy)
	; TW / 2 - xoffs

	ld a, 0 (ix)
	ld 4 (iy), a
	; xoffs

	ld 8 (iy), c
	; TW / 2 - xoffs

	call _put_sprite_rc

put_sprite4_reminder:
	ld a, 1 (ix)
	or a
	; yoffs
	jp z, put_sprite4_done

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * 20 * 3)
	add hl, bc
	; *tile + TMW * 3

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters
	ld a, 0 (ix)
	ld 2 (iy), a
	; xoffs

	xor a
	ld 3 (iy), a
	ld 8 (iy), a
	; 0

	ld a, #4
	sub 0 (ix)
	ld 4 (iy), a
	; TW / 2 - xoffs

	ld a, 1 (ix)
	ld 5 (iy), a
	; yoffs

	ld a, #(8 * 3)
	sub 1 (ix)
	ld 9 (iy), a
	; 3 * TH  - yoffs

	call _put_sprite_rc

	ld a, 0 (ix)
	or a
	jp z, put_sprite4_done

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * (20 * 3 + 1))
	add hl, bc
	; *tile + 3 * TMW + 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters that changed
	xor a
	ld 2 (iy), a
	; 0

	ld c, 4 (iy)
	; TW / 2 - xoffs

	ld a, 0 (ix)
	ld 4 (iy), a
	; xoffs

	ld 8 (iy), c
	; TW / 2 - xoffs

	ld a, #(8 * 3)
	sub 1 (ix)
	ld 9 (iy), a
	; 3 * TH  - yoffs

	call _put_sprite_rc

	jr put_sprite4_done

put_sprite4_reminder_th2:

	ld a, 1 (ix)
	or a
	; yoffs
	jr z, put_sprite4_done

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * 20 * 2)
	add hl, bc
	; *tile + TMW * 2

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters
	ld a, 0 (ix)
	ld 2 (iy), a
	; xoffs

	xor a
	ld 3 (iy), a
	ld 8 (iy), a
	; 0

	ld a, #4
	sub 0 (ix)
	ld 4 (iy), a
	; TW / 2 - xoffs

	ld a, 1 (ix)
	ld 5 (iy), a
	; yoffs

	ld a, #(8 * 2)
	sub 1 (ix)
	ld 9 (iy), a
	; 2 * TH  - yoffs

	call _put_sprite_rc

	ld a, 0 (ix)
	or a
	jr z, put_sprite4_done

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * (20 * 2 + 1))
	add hl, bc
	; *tile + 2 * TMW + 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters that changed
	xor a
	ld 2 (iy), a
	; 0

	ld c, 4 (iy)
	; TW / 2 - xoffs

	ld a, 0 (ix)
	ld 4 (iy), a
	; xoffs

	ld 8 (iy), c
	; TW / 2 - xoffs

	ld a, #(8 * 2)
	sub 1 (ix)
	ld 9 (iy), a
	; 2 * TH  - yoffs

	call _put_sprite_rc

	put_sprite4_done:
	ld hl, #15
	add hl, sp
	ld sp, hl

	ret

put_sprite4_reminder_th1:

	ld a, 1 (ix)
	or a
	; yoffs
	jr z, put_sprite4_done

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * 20 * 1)
	add hl, bc
	; *tile + TMW * 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters
	ld a, 0 (ix)
	ld 2 (iy), a
	; xoffs

	xor a
	ld 3 (iy), a
	ld 8 (iy), a
	; 0

	ld a, #4
	sub 0 (ix)
	ld 4 (iy), a
	; TW / 2 - xoffs

	ld a, 1 (ix)
	ld 5 (iy), a
	; yoffs

	ld a, #8
	sub 1 (ix)
	ld 9 (iy), a
	; TH  - yoffs

	call _put_sprite_rc

	ld a, 0 (ix)
	or a
	jr z, put_sprite4_done

	; *tile
	ld l, 11 (iy)
	ld h, 12 (iy)

	ld bc, #(8 * (20 * 1 + 1))
	add hl, bc
	; *tile + 1 * TMW + 1

	push hl
	; fastcall, does not use ix or iy
	call _link_buffer
	pop hl

	ld e, (hl)
	inc hl
	ld d, (hl)
	res #7, d
	; de has baddr & ADDR_BITS

	pop af
	push de
	; save parameter

	; update parameters that changed
	xor a
	ld 2 (iy), a
	; 0

	ld c, 4 (iy)
	; TW / 2 - xoffs

	ld a, 0 (ix)
	ld 4 (iy), a
	; xoffs

	ld 8 (iy), c
	; TW / 2 - xoffs

	ld a, #8
	sub 1 (ix)
	ld 9 (iy), a
	; TH  - yoffs

	call _put_sprite_rc

	jp put_sprite4_done

    __endasm;
    // *INDENT-ON*
}

uint8_t tink, fink, bink;
uint8_t tfont[16];

void _set_text_ink(uint8_t c, uint8_t *t)
{
    *t = ((c & 1) << 7) | ((c & 1) << 6) | ((c & 4) << 3) | ((c & 4) << 2)
         | ((c & 2) << 2) | ((c & 2) << 1) | ((c & 8) >> 2) | ((c & 8) >> 3);
}

void set_text_ink(uint8_t c, uint8_t c2, uint8_t c3)
{
    _set_text_ink(c, &tink);
    _set_text_ink(c2, &fink);
    _set_text_ink(c3, &bink);
}

#include <string.h>
void cpc_PutSp(char *sprite, char height, char width, int address);

void tint_text()
{
    // *INDENT-OFF*
    __asm;
	ld de, #_tfont

	ld hl, #_tink
	ld c, (hl)

	ld hl, #_fink
	ld a, (hl)

	ld hl, #_bink
	ld h, (hl)
        ld l, a

	ld b, #6
tint_loop1:
	ld a, (de)
	and c
	ld (de), a
	inc de

	djnz tint_loop1

	ld b, #6
tint_loop2:
	ld a, (de)
	and l
	ld (de), a
	inc de

	djnz tint_loop2

	ld b, #4
tint_loop3:
	ld a, (de)
	and h
	ld (de), a
	inc de

	djnz tint_loop3

    __endasm;
    // *INDENT-ON*
}

#pragma save
#pragma disable_warning 85
void put_text(const char *s, uint8_t x, uint8_t y)
{
    /*
       while(*s)
       {
    	   memcpy(tfont, spfont[*s - 31], 16);
    	   tint_text();
    	   cpc_PutSp(tfont, 8, 2, screen_addr(x, y));
    	   x += 2;
    	   s++;
       }
       */

    // *INDENT-OFF*
    __asm;
	ld hl, #2
	add hl, sp

	ld e, (hl)
	inc hl
	ld d, (hl) ; s
	inc hl
	ld b, (hl) ; x
	inc hl
	ld c, (hl) ; y

put_text_loop:
	push de
	push bc

	ld hl, #16
	push hl

	ld a, (de)
	sub #31
	ld l, a ; h is 0
	add hl, hl
	add hl, hl
	add hl, hl
	add hl, hl
	ld bc, #_spfont
	add hl, bc
	push hl

	ld hl, #_tfont
	push hl

	call _memcpy
	pop af
	pop af
	pop af

	call _tint_text

	pop hl
	push hl

	ld a, h
	ld h, #0
	push hl
	ld l, a
	push hl

	call _screen_addr
	pop af
	pop af

	push hl

	ld hl, #0x0208
	push hl

	ld hl, #_tfont
	push hl

	call _cpc_PutSp
	pop af
	pop af
	pop af

	pop bc
	pop de

	inc b
	inc b

	inc de
	ld a, (de)
	or #0
	jr nz, put_text_loop

    __endasm;
    // *INDENT-ON*
}
#pragma restore

#pragma save
#pragma disable_warning 85
void fill_screen(const uint8_t *t) __z88dk_fastcall
{
    // *INDENT-OFF*
    __asm;
    ex de, hl

    ld hl, #_tiles
    ld bc, #(TMW * TMH)

fill_screen_loop:
    inc hl
    inc hl

    ld (hl), e
    inc hl
    ld (hl), d
    inc hl

    inc hl
    inc hl
    inc hl
    inc hl

    dec bc
    ld a, c
    or b
    jr nz, fill_screen_loop

    jp _invalidate_screen
    __endasm;
    // *INDENT-ON*
}
#pragma restore

uint8_t abs_sub(uint8_t a, uint8_t b)
{
    /*
    if (a > b)
        return (a - b);
    else
        return (b - a);
    */
        // *INDENT-OFF*
        __asm;
        ld hl, #2
        add hl, sp
        ld b, (hl)
        inc hl
        ld c, (hl)
        ld a, b
        sub c
        jr c, b_minus_a
        ld l, a
        ret
b_minus_a:
        ld a, c
        sub b
        ld l, a
        __endasm;
        // *INDENT-ON*
}

// EOF