3 * (C) 2018 by Andreas Eversberg <jolly@eversberg.eu>
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include "../libcpu/m68k.h"
24 #include "mercenary.h"
26 #define INITIAL_STACK 0x7fffa
27 #define RESET_VECTOR 0x5a16c
28 // #define RESET_VECTOR 0x5a1a4 /* strange reset vector that causes the player to fly around */
29 const uint32_t mercenary_stop_at[] = {
30 0x5a826, /* done with rendering, waiting for VBL */
31 0x55d8c, /* after pressing 'HELP' key before showing menu line on benson */
32 0x56398, /* waiting for menu command */
33 0x55d94, /* after pressing 'HELP' key while showing menu line on benson */
34 0x563a6, /* after pressing 'RETURN' while game waits for other key to resume */
35 0x52946, /* after dying, waiting for VBL to fade out palette */
37 }; /* break points for rendering and continue with processing loop */
39 extern const uint32_t mercenary3_hex[];
40 extern int mercenary3_hex_size;
42 void mercenary_load(void)
46 /* load game binary from constant to volatile memory */
47 for (i = 0; i < mercenary3_hex_size; i += 4) {
48 m68k_write_memory_32(i, mercenary3_hex[i / 4]);
52 void mercenary_patch(void)
55 m68k_write_memory_32(0x00000, INITIAL_STACK);
58 m68k_write_memory_32(0x00004, RESET_VECTOR);
60 /* patch away the function call that is outside chip memory
61 * is this a copy protection????
63 m68k_write_memory_16(0x5a17c, 0x4e71); /* nop */
64 m68k_write_memory_16(0x5a17e, 0x4e71); /* nop */
65 m68k_write_memory_16(0x5a180, 0x4e71); /* nop */
67 /* remove wait for VBL */
68 m68k_write_memory_16(0x5a82C, 0x4e71); /* nop */
70 /* reduce loop that waits for disk stepper to move */
71 if (m68k_read_memory_32(0x562f8) != 0x000091b0) {
72 fprintf(stderr, "expecting loop counter of 0x000091b0 here, please fix!\n");
75 m68k_write_memory_32(0x562f8, 1);
76 /* reduce loop that waits for disk side change */
77 if (m68k_read_memory_32(0x55f5c) != 0x0000d020) {
78 fprintf(stderr, "expecting loop counter of 0x0000d020 here, please fix!\n");
81 m68k_write_memory_32(0x55f5c, 1);
84 uint32_t mercenary_palette(void)
86 return m68k_read_memory_32(0x0072b0);