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Optimize port_6x

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Try to avoid branching as this is a hot path in some machines
About 250% speedup
This commit is contained in:
Adrien Moulin
2022-07-10 15:14:55 +02:00
parent 04cabaa43e
commit 55cbbe79f7
1 changed files with 73 additions and 59 deletions
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132
src/port_6x.c
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@@ -71,70 +71,75 @@ port_6x_write(uint16_t port, uint8_t val, void *priv)
} }
} }
static uint8_t static uint8_t
port_6x_read(uint16_t port, void *priv) port_61_read_simple(uint16_t port, void *priv)
{ {
port_6x_t *dev = (port_6x_t *) priv; uint8_t ret = ppi.pb & 0x1f;
uint8_t ret = 0xff;
port &= 3; if (ppispeakon)
ret |= 0x20;
if ((port == 3) && (dev->flags & PORT_6X_MIRROR))
port = 1;
switch (port) {
case 1:
if (dev->flags & PORT_6X_EXT_REF) {
ret = ppi.pb & 0x0f;
if (dev->refresh)
ret |= 0x10;
} else
ret = ppi.pb & 0x1f;
if (ppispeakon)
ret |= 0x20;
if (dev->flags & PORT_6X_TURBO)
ret = (ret & 0xfb) | (xi8088_turbo_get() ? 0x04 : 0x00);
break;
case 2:
if (dev->flags & PORT_6X_SWA) {
/* SWA on Olivetti M240 mainboard (off=1) */
ret = 0x00;
if (ppi.pb & 0x8) {
/* Switches 4, 5 - floppy drives (number) */
int i, fdd_count = 0;
for (i = 0; i < FDD_NUM; i++) {
if (fdd_get_flags(i))
fdd_count++;
}
if (!fdd_count)
ret |= 0x00;
else
ret |= ((fdd_count - 1) << 2);
/* Switches 6, 7 - monitor type */
if (video_is_mda())
ret |= 0x3;
else if (video_is_cga())
ret |= 0x2; /* 0x10 would be 40x25 */
else
ret |= 0x0;
} else {
/* bit 2 always on */
ret |= 0x4;
/* Switch 8 - 8087 FPU. */
if (hasfpu)
ret |= 0x02;
}
}
break;
}
return(ret); return(ret);
} }
static uint8_t
port_61_read(uint16_t port, void *priv)
{
port_6x_t *dev = (port_6x_t *) priv;
uint8_t ret = 0xff;
if (dev->flags & PORT_6X_EXT_REF) {
ret = ppi.pb & 0x0f;
if (dev->refresh)
ret |= 0x10;
} else
ret = ppi.pb & 0x1f;
if (ppispeakon)
ret |= 0x20;
if (dev->flags & PORT_6X_TURBO)
ret = (ret & 0xfb) | (xi8088_turbo_get() ? 0x04 : 0x00);
return(ret);
}
static uint8_t
port_62_read(uint16_t port, void *priv)
{
uint8_t ret = 0xff;
/* SWA on Olivetti M240 mainboard (off=1) */
ret = 0x00;
if (ppi.pb & 0x8) {
/* Switches 4, 5 - floppy drives (number) */
int i, fdd_count = 0;
for (i = 0; i < FDD_NUM; i++) {
if (fdd_get_flags(i))
fdd_count++;
}
if (!fdd_count)
ret |= 0x00;
else
ret |= ((fdd_count - 1) << 2);
/* Switches 6, 7 - monitor type */
if (video_is_mda())
ret |= 0x3;
else if (video_is_cga())
ret |= 0x2; /* 0x10 would be 40x25 */
else
ret |= 0x0;
} else {
/* bit 2 always on */
ret |= 0x4;
/* Switch 8 - 8087 FPU. */
if (hasfpu)
ret |= 0x02;
}
return(ret);
}
static void static void
port_6x_refresh(void *priv) port_6x_refresh(void *priv)
@@ -165,10 +170,19 @@ port_6x_init(const device_t *info)
dev->flags = info->local & 0xff; dev->flags = info->local & 0xff;
io_sethandler(0x0061, 3, port_6x_read, NULL, NULL, port_6x_write, NULL, NULL, dev); if (!(dev->flags & PORT_6X_TURBO) || (dev->flags & PORT_6X_EXT_REF))
io_sethandler(0x0061, 1, port_61_read_simple, NULL, NULL, port_6x_write, NULL, NULL, dev);
else
io_sethandler(0x0061, 1, port_61_read, NULL, NULL, port_6x_write, NULL, NULL, dev);
if (dev->flags & PORT_6X_SWA)
io_sethandler(0x0062, 1, port_62_read, NULL, NULL, NULL, NULL, NULL, dev);
if (dev->flags & PORT_6X_MIRROR)
io_sethandler(0x0063, 1, port_61_read, NULL, NULL, port_6x_write, NULL, NULL, dev);
if (dev->flags & PORT_6X_EXT_REF) if (dev->flags & PORT_6X_EXT_REF)
timer_add(&dev->refresh_timer, port_6x_refresh, dev, 1); timer_add(&dev->refresh_timer, port_6x_refresh, dev, 1);
return dev; return dev;
} }