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Mockingboard: replicate 6522 I/O across entire $Cnxx I/O space

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. SSI263.b7 not readable
. SSI263 writes also written to 6522 in low addr
This commit is contained in:
tomcw 2020-04-25 16:42:50 +01:00
parent 9f49820a8d
commit 389b6e6d23
1 changed files with 7 additions and 9 deletions
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16
source/Mockingboard.cpp
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@ -1601,14 +1601,11 @@ static BYTE __stdcall MB_Read(WORD PC, WORD nAddr, BYTE bWrite, BYTE nValue, ULO
return bAccessedDevice ? nRes : MemReadFloatingBus(nExecutedCycles);
}
if(nOffset <= (SY6522A_Offset+0x0F))
// NB. Mockingboard: SSI263.bit7 not readable (TODO: check this with real h/w)
if (nOffset < SY6522B_Offset)
return SY6522_Read(nMB*NUM_DEVS_PER_MB + SY6522_DEVICE_A, nAddr&0xf);
else if((nOffset >= SY6522B_Offset) && (nOffset <= (SY6522B_Offset+0x0F)))
return SY6522_Read(nMB*NUM_DEVS_PER_MB + SY6522_DEVICE_B, nAddr&0xf);
// else if((nOffset >= SSI263_Offset) && (nOffset <= (SSI263_Offset+0x07)))
// return SSI263_Read(nMB*2+1, nExecutedCycles); // SSI263 only drives bit7 -- TODO confirm with real MB h/w
else
return MemReadFloatingBus(nExecutedCycles);
return SY6522_Read(nMB*NUM_DEVS_PER_MB + SY6522_DEVICE_B, nAddr&0xf);
}
//-----------------------------------------------------------------------------
@ -1669,11 +1666,12 @@ static BYTE __stdcall MB_Write(WORD PC, WORD nAddr, BYTE bWrite, BYTE nValue, UL
return 0;
}
if(nOffset <= (SY6522A_Offset+0x0F))
if (nOffset < SY6522B_Offset)
SY6522_Write(nMB*NUM_DEVS_PER_MB + SY6522_DEVICE_A, nAddr&0xf, nValue);
else if((nOffset >= SY6522B_Offset) && (nOffset <= (SY6522B_Offset+0x0F)))
else
SY6522_Write(nMB*NUM_DEVS_PER_MB + SY6522_DEVICE_B, nAddr&0xf, nValue);
else if((nOffset >= SSI263_Offset) && (nOffset <= (SSI263_Offset+0x07)))
if ((nOffset >= SSI263_Offset) && (nOffset <= (SSI263_Offset+0x07)))
SSI263_Write(nMB*2+1, nAddr&0x7, nValue); // Second 6522 is used for speech chip -- TODO confirm with real MB h/w that writes go to 1st 6522
return 0;