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improve igs028

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This commit is contained in:
David Haywood 2013-10-14 01:57:14 +00:00
parent c905c30939
commit d927a35286
1 changed files with 38 additions and 16 deletions
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54
src/mame/machine/igs028.c
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@ -94,16 +94,21 @@ void igs028_device::IGS028_do_dma(UINT16 src, UINT16 dst, UINT16 size, UINT16 mo
mode &= 0x0f;
switch (mode)
switch (mode & 0x7)
{
case 0x00: // This mode copies code later on in the game! Encrypted somehow?
// src:2fc8, dst: 045a, size: 025e, mode: 0000
// jumps from 12beb4 in unprotected set
// jumps from 1313e0 in protected set
case 0x01: // swap bytes and nibbles
// igs022 has an 'IGS ' encryption mode, a plain copy, and a NOP, these aren't covered at the moment..
case 0x00: // -= encryption
case 0x01: // swap nibbles
case 0x02: // ^= encryption
case 0x05: // copy
case 0x03: // unused?
case 0x04: // unused?
case 0x05: // swap bytes
case 0x06: // += encryption (correct?)
case 0x07: // unused?
{
UINT8 extraoffset = param & 0xff;
UINT8 *dectable = (UINT8 *)(PROTROM + (0x100 / 2));
@ -115,21 +120,38 @@ void igs028_device::IGS028_do_dma(UINT16 src, UINT16 dst, UINT16 size, UINT16 mo
int taboff = ((x*2)+extraoffset) & 0xff; // must allow for overflow in instances of odd offsets
unsigned short extraxor = ((dectable[taboff + 0]) << 0) | (dectable[taboff + 1] << 8);
if (mode==0) dat2 = 0x4e75; // hack
if (mode==1) dat2 = ((dat2 & 0xf000) >> 12) | ((dat2 & 0x0f00) >> 4) | ((dat2 & 0x00f0) << 4) | ((dat2 & 0x000f) << 12);
if (mode==2) dat2 ^= extraxor;
// if (mode==5) dat2 = dat2;
if (mode==6) dat2 += extraxor;
if (mode==0) dat2 -= extraxor;
else if (mode==1) dat2 = ((dat2 & 0xf0f0) >> 4)|((dat2 & 0x0f0f) << 4);
else if (mode==2) dat2 ^= extraxor;
else if (mode==5) dat2 = ((dat2 &0x00ff) << 8) | ((dat2 &0xff00) >> 8);
else if (mode==6) dat2 += extraxor;
else
{
// if other modes are used we need to know about them
UINT16 extraxor2 = 0;
if ((x & 0x003) == 0x000) extraxor2 |= 0x0049; // 'I'
if ((x & 0x003) == 0x001) extraxor2 |= 0x0047; // 'G'
if ((x & 0x003) == 0x002) extraxor2 |= 0x0053; // 'S'
if ((x & 0x003) == 0x003) extraxor2 |= 0x0020; // ' '
if (mode==2 || mode==6) dat2 = (dat2<<8)|(dat2>>8);
m_sharedprotram[dst + x] = (dat2 << 8) | (dat2 >> 8);
if ((x & 0x300) == 0x000) extraxor2 |= 0x4900; // 'I'
if ((x & 0x300) == 0x100) extraxor2 |= 0x4700; // 'G'
if ((x & 0x300) == 0x200) extraxor2 |= 0x5300; // 'S'
if ((x & 0x300) == 0x300) extraxor2 |= 0x2000; // ' '
printf("mode %d - %04x (%04x %04x %04x - %04x %04x %04x - %04x %04x \n", mode, dat2, (UINT16)(dat2-extraxor), (UINT16)(dat2+extraxor), (UINT16)(dat2^extraxor), (UINT16)(dat2-extraxor2), (UINT16)(dat2+extraxor2), (UINT16)(dat2^extraxor2), ((dat2 & 0xf0f0) >> 4)|((dat2 & 0x0f0f) << 4), ((dat2 &0x00ff) << 8) | ((dat2 &0xff00) >> 8) );
dat2 = 0x4e75; // hack
}
m_sharedprotram[dst + x] = dat2;
}
}
break;
// default:
// logerror ("DMA mode unknown!!!\nsrc:%4.4x, dst: %4.4x, size: %4.4x, mode: %4.4x\n", src, dst, size, mode);
default: // >=8
printf ("DMA mode unknown!!!\nsrc:%4.4x, dst: %4.4x, size: %4.4x, mode: %4.4x\n", src, dst, size, mode);
}
}