diff options
| author | 2021-02-20 14:35:50 +0900 | |
|---|---|---|
| committer | 2021-02-20 06:35:50 +0100 | |
| commit | 6dfcaef06fdfe47e74ca14ba8cbd044a2523aaeb (patch) | |
| tree | d81848d1eda5e017c6e484d8abdbd2101da0a72c | |
| parent | d913d6ed606ee002e82e2e46f4e6c541efbc6652 (diff) | |
315_5313.cpp: Fix/Add hardware related notes (#7567)
| -rw-r--r-- | src/devices/video/315_5313.cpp | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/src/devices/video/315_5313.cpp b/src/devices/video/315_5313.cpp index 69f86f67ccc..d1cc757f7ba 100644 --- a/src/devices/video/315_5313.cpp +++ b/src/devices/video/315_5313.cpp @@ -1,6 +1,15 @@ // license:BSD-3-Clause // copyright-holders:David Haywood -/* Sega 315-5313 - Megadrive VDP */ +/* + Sega 315-5313 VDP emulation, used by Mega Drive/Genesis + + TODO: + - Video, DMA timing and HV counter is seems to incorrect, + Needs verifications from real hardware. + - Support 128KB VRAM configuration, Any hardware used it? + - Border area is displayable? + - 32X overlay with H32 mode, all known software used this? +*/ #include "emu.h" #include "video/315_5313.h" @@ -159,7 +168,7 @@ static const unsigned hres_mul[4] = { 5, 5, 4, 4 }; inline u8 sega315_5313_device::get_hres() { return (MEGADRIVE_REG0C_RS0 | (MEGADRIVE_REG0C_RS1 << 1)) & 3; } int sega315_5313_device::screen_hpos() { return screen().hpos() / (m_lcm_scaling ? hres_mul[get_hres()] : 1); } -#define MAX_HPOSITION 480 +#define MAX_HPOSITION 480 // TODO: 342(H32) or 427.5(H40), each scanline used 3420 cycle DEFINE_DEVICE_TYPE(SEGA315_5313, sega315_5313_device, "sega315_5313", "Sega 315-5313 Megadrive VDP") @@ -2321,7 +2330,7 @@ void sega315_5313_device::vdp_handle_eof() if (MEGADRIVE_REG01_240_LINE) { - /* this is invalid in PAL! */ + /* this is invalid in NTSC! */ m_total_scanlines = m_base_total_scanlines; m_visible_scanlines = 240; m_irq6_scanline = 240; |
