The-Homebrew-Cloud/Genesis-Plus-GX
2
0
Fork 0
mirror of https://github.com/ekeeke/Genesis-Plus-GX.git synced 2024-11-13 06:15:07 +01:00
Code Issues Packages Projects Releases Wiki Activity

[Core/VDP] improved DMA timing accuracy during blanking (verified on real hardware by Mask of Destiny)

Browse Source
This commit is contained in:
EkeEke 2017-06-24 15:59:44 +02:00
parent 38ffc317cb
commit 4017d379e6
5 changed files with 11 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
HISTORY.txt
View File

@ -105,6 +105,7 @@ Genesis Plus GX 1.7.5 (xx/xx/xxxx) (Eke-Eke)
* improved FIFO timings accuracy (fixes "Overdrive" Demo)
* improved H-Counter accuracy in H32 mode
* improved VDP status timing accuracy
* improved DMA timing accuracy during blanking (verified on real hardware by Mask of Destiny)
* improved accuracy of Master System color palette brightness range (verified against real hardware)
* fixed misaligned buffer writes in Mode 4 when -DALIGN_LONG option is used
* fixed alpha channel for 15-bit (RGB555) and 32-bit (RGB888) color support

BIN
builds/genesis_plus_gx_libretro.dll
View File

Binary file not shown.

BIN
builds/genplus_cube.dol
View File

Binary file not shown.
Side by Side Swipe Overlay

Before

Width:  |  Height:  |  Size: 3.2 MiB

After

Width:  |  Height:  |  Size: 3.2 MiB

BIN
builds/genplus_wii.dol
View File

Binary file not shown.
Side by Side Swipe Overlay

Before

Width:  |  Height:  |  Size: 3.3 MiB

After

Width:  |  Height:  |  Size: 3.3 MiB

20
core/vdp_ctrl.c
View File

@ -161,7 +161,7 @@ static const uint8 dma_timing[2][2] =
{
/* H32, H40 */
{16 , 18}, /* active display */
{167, 205} /* blank display */
{166, 204} /* blank display */
};
/* DMA processing functions (set by VDP register 23 high nibble) */
@ -560,19 +560,16 @@ void vdp_dma_update(unsigned int cycles)
/* DMA transfer rate (bytes per line)
According to the manual, here's a table that describes the transfer
rates of each of the three DMA types:
DMA Mode Width Display Transfer Count
-----------------------------------------------------
68K > VDP 32-cell Active 16
Blanking 167
40-cell Active 18
Blanking 205
VRAM Fill 32-cell Active 15
Blanking 166
40-cell Active 17
40-cell Active 18
Blanking 204
VRAM Fill 32-cell Active 15
Blanking 165
40-cell Active 17
Blanking 203
VRAM Copy 32-cell Active 8
Blanking 83
40-cell Active 9
@ -897,7 +894,10 @@ void vdp_z80_ctrl_w(unsigned int data)
{
case 2:
{
/* DMA Fill will be triggered by next write to DATA port */
/* DMA Fill */
dma_type = 2;
/* DMA is pending until next DATA port write */
dmafill = 1;
/* Set DMA Busy flag */