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 "../libcpu/execute.h"
25 #include "mercenary.h"
27 #define INITIAL_STACK 0x7fffa
28 #define RESET_VECTOR 0x5a16c
29 // #define RESET_VECTOR 0x5a1a4 /* strange reset vector that causes the player to fly around */
31 /* interrupt CPU execution at special break points and tell emulation what to do */
32 const struct cpu_stop mercenary_stop_at[] = {
33 { 0x5a826, STOP_AT_WAIT_VBL }, /* done with rendering, waiting for VBL */
34 { 0x55d8c, STOP_AT_WAIT_VBL }, /* after pressing 'HELP' key before showing menu line on benson */
35 { 0x56398, STOP_AT_WAIT_VBL }, /* waiting for menu command */
36 { 0x55d94, STOP_AT_WAIT_VBL }, /* after pressing 'HELP' key while showing menu line on benson */
37 { 0x563a6, STOP_AT_WAIT_VBL }, /* after pressing 'RETURN' while game waits for other key to resume */
38 { 0x52946, STOP_AT_WAIT_VBL }, /* after dying, waiting for VBL to fade out palette */
39 { 0x0, STOP_AT_END }, /* end */
42 extern const uint32_t mercenary3_hex[];
43 extern int mercenary3_hex_size;
45 void mercenary_load(void)
49 /* load game binary from constant to volatile memory */
50 for (i = 0; i < mercenary3_hex_size; i += 4) {
51 m68k_write_memory_32(i, mercenary3_hex[i / 4]);
55 void mercenary_patch(void)
58 m68k_write_memory_32(0x00000, INITIAL_STACK);
61 m68k_write_memory_32(0x00004, RESET_VECTOR);
63 /* patch away the function call that is outside chip memory
64 * is this a copy protection????
66 m68k_write_memory_16(0x5a17c, 0x4e71); /* nop */
67 m68k_write_memory_16(0x5a17e, 0x4e71); /* nop */
68 m68k_write_memory_16(0x5a180, 0x4e71); /* nop */
70 /* remove wait for VBL */
71 m68k_write_memory_16(0x5a82C, 0x4e71); /* nop */
73 /* reduce loop that waits for disk stepper to move */
74 if (m68k_read_memory_32(0x562f8) != 0x000091b0) {
75 fprintf(stderr, "expecting loop counter of 0x000091b0 here, please fix!\n");
78 m68k_write_memory_32(0x562f8, 1);
79 /* reduce loop that waits for disk side change */
80 if (m68k_read_memory_32(0x55f5c) != 0x0000d020) {
81 fprintf(stderr, "expecting loop counter of 0x0000d020 here, please fix!\n");
84 m68k_write_memory_32(0x55f5c, 1);
87 uint32_t mercenary_palette(void)
89 return m68k_read_memory_32(0x0072b0);
92 const char *mercenary_gamesavesuffix = ".m3save";