1 /* Mednafen - Multi-system Emulator
2 *
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 */
17
18 #include "../shared.h"
19 #include "cd.h"
20 #include "interrupt.h"
21
22 /* SegaCD interrupt levels:
23 6 - Sub-channel buffering completed
24 5 - CDC, error correction or buffer completed
25 4 - CDD, command reception is completed?
26 3 - Timer
27 2 - Software int from main CPU
28 1 - Graphics operation is completed
29 */
30
31
32 static uint32 asserted;
33 static uint32 InterruptMask;
34
Rebuild(void)35 static void Rebuild(void)
36 {
37 int pending_level = 0;
38 uint32 awm = asserted & InterruptMask;
39
40 // Level 0 doesn't exist per-se.
41 // Level 7 doesn't seem to be used on the SegaCD
42 for(int i = 6; i > 0; i--)
43 {
44 if(awm & (1 << i))
45 {
46 pending_level = i;
47 break;
48 }
49 }
50
51 Sub68K.SetIPL(pending_level);
52 }
53
MDCD_InterruptRead(void)54 uint8 MDCD_InterruptRead(void)
55 {
56 return(InterruptMask);
57 }
58
MDCD_InterruptGetMask(int level)59 bool MDCD_InterruptGetMask(int level)
60 {
61 return((InterruptMask >> level) & 1);
62 }
63
MDCD_InterruptGetAsserted(int level)64 bool MDCD_InterruptGetAsserted(int level)
65 {
66 return((asserted >> level) & 1);
67 }
68
MDCD_InterruptWrite(uint8 V)69 void MDCD_InterruptWrite(uint8 V)
70 {
71 InterruptMask = V & 0x7E;
72 Rebuild();
73 }
74
MDCD_InterruptAck(int level)75 int MDCD_InterruptAck(int level)
76 {
77 printf("Interrupt: %d\n", level);
78
79 asserted &= ~(1 << level);
80 Rebuild();
81
82 return M68K::BUS_INT_ACK_AUTO;
83 }
84
MDCD_InterruptAssert(int level,bool status)85 void MDCD_InterruptAssert(int level, bool status)
86 {
87 assert(status == 0 || status == 1);
88
89 asserted &= ~(1 << level);
90 asserted |= status << level;
91 Rebuild();
92 }
93
MDCD_InterruptReset(void)94 void MDCD_InterruptReset(void)
95 {
96 asserted = 0;
97 Rebuild();
98 }
99
MDCD_InterruptInit(void)100 void MDCD_InterruptInit(void)
101 {
102
103
104 }
105