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Diffstat (limited to 'src/devices/bus/neogeo/pcm2_prot.c')
-rw-r--r--src/devices/bus/neogeo/pcm2_prot.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/src/devices/bus/neogeo/pcm2_prot.c b/src/devices/bus/neogeo/pcm2_prot.c
new file mode 100644
index 00000000000..6ee156712e9
--- /dev/null
+++ b/src/devices/bus/neogeo/pcm2_prot.c
@@ -0,0 +1,88 @@
+// license:BSD-3-Clause
+// copyright-holders:S. Smith,David Haywood
+
+
+#include "emu.h"
+#include "pcm2_prot.h"
+
+
+
+extern const device_type PCM2_PROT = &device_creator<pcm2_prot_device>;
+
+
+pcm2_prot_device::pcm2_prot_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, PCM2_PROT, "NeoGeo Protection (NEOPCM2)", tag, owner, clock, "pcm2_prot", __FILE__)
+{
+}
+
+
+void pcm2_prot_device::device_start()
+{
+}
+
+void pcm2_prot_device::device_reset()
+{
+}
+
+/***************************************************************************
+
+NeoGeo 'V' (PCM) ROM encryption
+ NEOPCM2 chip
+
+***************************************************************************/
+
+/* Neo-Pcm2 Drivers for Encrypted V Roms */
+void pcm2_prot_device::neo_pcm2_snk_1999(UINT8* ymrom, UINT32 ymsize, int value)
+{ /* thanks to Elsemi for the NEO-PCM2 info */
+ UINT16 *rom = (UINT16 *)ymrom;
+ int size = ymsize;
+ int i, j;
+
+ if( rom != NULL )
+ { /* swap address lines on the whole ROMs */
+ std::vector<UINT16> buffer(value / 2);
+
+ for( i = 0; i < size / 2; i += ( value / 2 ) )
+ {
+ memcpy( &buffer[0], &rom[ i ], value );
+ for( j = 0; j < (value / 2); j++ )
+ {
+ rom[ i + j ] = buffer[ j ^ (value/4) ];
+ }
+ }
+ }
+}
+
+
+/* the later PCM2 games have additional scrambling */
+void pcm2_prot_device::neo_pcm2_swap(UINT8* ymrom, UINT32 ymsize, int value)
+{
+ static const UINT32 addrs[7][2]={
+ {0x000000,0xa5000},
+ {0xffce20,0x01000},
+ {0xfe2cf6,0x4e001},
+ {0xffac28,0xc2000},
+ {0xfeb2c0,0x0a000},
+ {0xff14ea,0xa7001},
+ {0xffb440,0x02000}};
+ static const UINT8 xordata[7][8]={
+ {0xf9,0xe0,0x5d,0xf3,0xea,0x92,0xbe,0xef},
+ {0xc4,0x83,0xa8,0x5f,0x21,0x27,0x64,0xaf},
+ {0xc3,0xfd,0x81,0xac,0x6d,0xe7,0xbf,0x9e},
+ {0xc3,0xfd,0x81,0xac,0x6d,0xe7,0xbf,0x9e},
+ {0xcb,0x29,0x7d,0x43,0xd2,0x3a,0xc2,0xb4},
+ {0x4b,0xa4,0x63,0x46,0xf0,0x91,0xea,0x62},
+ {0x4b,0xa4,0x63,0x46,0xf0,0x91,0xea,0x62}};
+
+ dynamic_buffer buf(0x1000000);
+ int i, j, d;
+ UINT8* src = ymrom;
+ memcpy(&buf[0],src,0x1000000);
+ for (i=0;i<0x1000000;i++)
+ {
+ j=BITSWAP24(i,23,22,21,20,19,18,17,0,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,16);
+ j=j^addrs[value][1];
+ d=((i+addrs[value][0])&0xffffff);
+ src[j]=buf[d]^xordata[value][j&0x7];
+ }
+}