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added proper HV Counter latch support, as verified on real hardware (fixes Sunset Riders intro)

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ekeeke31 2010-05-17 10:59:47 +00:00
parent bbf44f27d0
commit 5078244cd1
4 changed files with 29 additions and 12 deletions
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4
HISTORY.txt
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@ -25,6 +25,7 @@ of samples per frame and keeping PSG & FM chips in sync.
---------------
* added support for CRAM writes during horizontal blanking (Striker, Zero the Kamikaze Squirrel,...)
* added support for 2-Cell vertical scrolling in Interlaced 2 mode
* added proper HV Counter latch support (fixes Sunset Riders intro)
* fixed left-most column vertical scrolling when horizontally scrolled (Gynoug, F1)
* fixed VBLANK transition line checks
* improved VDP FIFO timings accuracy: fixes Sol Deace intro
@ -32,9 +33,10 @@ of samples per frame and keeping PSG & FM chips in sync.
* improved HBLANK flag timing accuracy: fixes Mega Turrican (Sky level)
* improved sprites processing accuracy: fixes (un)masked sprites in Mickey Mania (3D level), Sonic 2 (VS mode).
* improved horizontal blanking & HINT/VINT occurence timing accuracy, as measured on real hardware.
* improved H-Counter accuracy in 40-cell mode, as measured on real hardware.
* improved HCounter accuracy in 40-cell mode, as measured on real hardware.
* improved color accuracy in VDP highlight mode to match results observed on real hardware.
[Core/CPU]
---------------
* updated Z80 core to last version (fixes interrupt Mode 0 timing and some BIT instructions).

15
source/gen_input.c
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@ -90,16 +90,17 @@ static inline void lightgun_update(int num)
if (reg[11] & 0x08)
irq_status = (irq_status & ~0x40) | 0x12;
/* Horizontal Counter Latch:
1) some games does not set HVC latch but instead use bigger X offset
2) for games using H40 mode, the gun routine scales up the Hcounter value,
H-Counter range is approx. 292 pixel clocks
/* HV Counter Latch:
1) some games does not enable HVC latch but instead use bigger X offset
--> we force the HV counter value read by the gun routine
2) for games using H40 mode, the gun routine scales up the Hcounter value
--> H-Counter range is approx. 290 dot clocks
*/
hc_latch = 0x100;
hvc_latch = 0x10000 | (vctab[v_counter] << 8);
if (reg[12] & 1)
hc_latch |= hc_320[((input.analog[num][0] * 290) / (2 * 320) + input.x_offset) % 210];
hvc_latch |= hc_320[((input.analog[num][0] * 290) / (2 * 320) + input.x_offset) % 210];
else
hc_latch |= hc_256[(input.analog[num][0] / 2 + input.x_offset)%171];
hvc_latch |= hc_256[(input.analog[num][0] / 2 + input.x_offset)%171];
}
}
}

20
source/vdp.c
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@ -66,8 +66,8 @@ uint8 bg_pattern_cache[0x80000]; /* Cached and flipped patterns */
uint8 playfield_shift; /* Width of planes A, B (in bits) */
uint8 playfield_col_mask; /* Vertical scroll mask */
uint16 playfield_row_mask; /* Horizontal scroll mask */
uint16 hc_latch; /* latched HCounter (INT2) */
uint16 v_counter; /* VDP scanline counter */
uint32 hvc_latch; /* latched HVCounter (INT2) */
uint32 dma_length; /* Current DMA remaining bytes */
int32 fifo_write_cnt; /* VDP writes fifo count */
uint32 fifo_lastwrite; /* last VDP write cycle */
@ -161,7 +161,7 @@ void vdp_reset(void)
hint_pending = 0;
vint_pending = 0;
irq_status = 0;
hc_latch = 0;
hvc_latch = 0;
v_counter = 0;
dmafill = 0;
dma_length = 0;
@ -455,8 +455,12 @@ unsigned int vdp_ctrl_r(void)
unsigned int vdp_hvc_r(void)
{
/* HVC is frozen (Lightgun games + Sunset Riders) */
if (hvc_latch)
return (hvc_latch & 0xffff);
/* Horizontal Counter (Striker, Mickey Mania, Skitchin, Road Rash I,II,III, ...) */
uint8 hc = (hc_latch & 0x100) ? (hc_latch & 0xFF) : hctab[mcycles_68k%MCYCLES_PER_LINE];
uint8 hc = hctab[mcycles_68k%MCYCLES_PER_LINE];
/* Vertical Counter */
uint8 vc = vctab[v_counter];
@ -780,6 +784,16 @@ static void reg_w(unsigned int r, unsigned int d)
for (i = 1; i < 0x40; i += 1)
color_update (i, *(uint16 *) & cram[i << 1]);
}
/* HVC latch bit */
if (r & 0x02)
{
if (reg[0] & 2) /* latch current HVC */
hvc_latch = 0x10000 | (vctab[v_counter] << 8) | hctab[mcycles_68k%MCYCLES_PER_LINE];
else /* free-running HVC */
hvc_latch = 0;
}
break;
case 1: /* CTRL #2 */

2
source/vdp.h
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@ -54,8 +54,8 @@ extern uint8 bg_pattern_cache[0x80000];
extern uint8 playfield_shift;
extern uint8 playfield_col_mask;
extern uint16 playfield_row_mask;
extern uint16 hc_latch;
extern uint16 v_counter;
extern uint32 hvc_latch;
extern uint32 dma_length;
extern int32 fifo_write_cnt;
extern uint32 fifo_lastwrite;