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Fixed 2 bugs in the floating bus code.

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The Bulgarian game "Walking in the town" now works.
Also improved the layout of the FB code, and added references to Understanding The Apple IIe for all the important logic and boolean equations used.
This commit is contained in:
nick_westgate 2008-12-30 15:45:48 +00:00
parent 7e83d61696
commit 779d2d4385
1 changed files with 40 additions and 36 deletions
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76
AppleWin/source/Video.cpp
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@ -680,7 +680,7 @@ void DrawHiResSourceHalfShiftDim ()
2400:83 1---0011 -> 1 1 0 0 half-pixel shift right
2800:06 1---0110 -> 0 1 1 0 column 2 & 3
@reference: see Beagle Bro's Disk: "Silicon Salid", File: DOUBLE HI-RES
@reference: see Beagle Bro's Disk: "Silicon Salad", File: DOUBLE HI-RES
Fortunately double-hires is supported via pixel doubling, so we can do half-pixel shifts ;-)
*/
switch (color)
@ -2294,7 +2294,10 @@ DWORD VideoSetSnapshot(SS_IO_Video* pSS)
}
//===========================================================================
//
// References to Jim Sather's books are given as eg:
// UTAIIe:5-7,P3 (Understanding the Apple IIe, chapter 5, page 7, Paragraph 3)
//
WORD VideoGetScannerAddress(bool* pbVblBar_OUT, const DWORD uExecutedCycles)
{
// get video scanner position
@ -2303,8 +2306,8 @@ WORD VideoGetScannerAddress(bool* pbVblBar_OUT, const DWORD uExecutedCycles)
// machine state switches
//
int nHires = (SW_HIRES & !SW_TEXT) ? 1 : 0;
int nPage2 = (SW_PAGE2) ? 1 : 0;
int nHires = (SW_HIRES && !SW_TEXT) ? 1 : 0;
int nPage2 = (SW_PAGE2) ? 1 : 0;
int n80Store = (MemGet80Store()) ? 1 : 0;
// calculate video parameters according to display standard
@ -2348,43 +2351,51 @@ WORD VideoGetScannerAddress(bool* pbVblBar_OUT, const DWORD uExecutedCycles)
// calculate scanning memory address
//
if (SW_HIRES && SW_MIXED && (v_4 & v_2)) // NICK: Should this be (SW_HIRES && !SW_TEXT) instead of just 'SW_HIRES' ?
if (nHires && SW_MIXED && v_4 && v_2) // HIRES TIME signal (UTAIIe:5-7,P3)
{
nHires = 0; // (address is in text memory)
nHires = 0; // address is in text memory for mixed hires
}
int nAddend0 = 0x68; // 1 1 0 1
int nAddend1 = (h_5 << 5) | (h_4 << 4) | (h_3 << 3);
int nAddend2 = (v_4 << 6) | (v_3 << 5) | (v_4 << 4) | (v_3 << 3);
int nSum = (nAddend0 + nAddend1 + nAddend2) & (0x0F << 3);
int nAddend0 = 0x0D; // 1 1 0 1
int nAddend1 = (h_5 << 2) | (h_4 << 1) | (h_3 << 0);
int nAddend2 = (v_4 << 3) | (v_3 << 2) | (v_4 << 1) | (v_3 << 0);
int nSum = (nAddend0 + nAddend1 + nAddend2) & 0x0F; // SUM (UTAIIe:5-9)
int nAddress = 0; // build address from video scanner equations (UTAIIe:5-8,T5.1)
nAddress |= h_0 << 0; // a0
nAddress |= h_1 << 1; // a1
nAddress |= h_2 << 2; // a2
nAddress |= nSum << 3; // a3 - a6
nAddress |= v_0 << 7; // a7
nAddress |= v_1 << 8; // a8
nAddress |= v_2 << 9; // a9
int p2a = 1 ^ (nPage2 & (1 ^ n80Store));
int p2b = nPage2 & (1 ^ n80Store);
int nAddress = 0;
nAddress |= h_0 << 0; // a0
nAddress |= h_1 << 1; // a1
nAddress |= h_2 << 2; // a2
nAddress |= nSum; // a3 - aa6
nAddress |= v_0 << 7; // a7
nAddress |= v_1 << 8; // a8
nAddress |= v_2 << 9; // a9
nAddress |= ((nHires) ? v_A : (1 ^ (nPage2 & (1 ^ n80Store)))) << 10; // a10
nAddress |= ((nHires) ? v_B : (nPage2 & (1 ^ n80Store))) << 11; // a11
if (nHires) // hires?
{
// Y: insert hires only address bits
// Y: insert hires-only address bits
//
nAddress |= v_A << 10; // a10
nAddress |= v_B << 11; // a11
nAddress |= v_C << 12; // a12
nAddress |= (1 ^ (nPage2 & (1 ^ n80Store))) << 13; // a13
nAddress |= (nPage2 & (1 ^ n80Store)) << 14; // a14
nAddress |= p2a << 13; // a13
nAddress |= p2b << 14; // a14
}
else
{
// N: text, so no higher address bits unless Apple ][, not Apple //e
// N: insert text-only address bits
//
if ((IS_APPLE2) && // Apple ][?
(kHPEClock <= nHClock) && // Y: HBL?
(nHClock <= (kHClocks - 1)))
nAddress |= p2a << 10; // a10
nAddress |= p2b << 11; // a11
// Apple ][ (not //e) and HBL?
//
if (IS_APPLE2 && // Apple II only (UTAIIe:I-4,#5)
((1 ^ h_5) & ((1 ^ h_3) | (1 ^ h_4)))) // HBL (UTAIIe:8-10,F8.5)
{
nAddress |= 1 << 12; // Y: a12 (add $1000 to address!)
nAddress |= 1 << 12; // Y: a12 (add $1000; )
}
}
@ -2392,14 +2403,7 @@ WORD VideoGetScannerAddress(bool* pbVblBar_OUT, const DWORD uExecutedCycles)
//
if (pbVblBar_OUT != NULL)
{
if (v_4 & v_3) // VBL?
{
*pbVblBar_OUT = false; // Y: VBL' is false
}
else
{
*pbVblBar_OUT = true; // N: VBL' is true
}
*pbVblBar_OUT = ((v_4 & v_3) == 0); // VBL' = (v_4 & v_3)' (UTAIIe:5-10,#3)
}
return static_cast<WORD>(nAddress);
}