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SiS 85c46x and 471 - implement AT bus speed configuration.

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This commit is contained in:
OBattler
2025-05-18 08:37:02 +02:00
parent 76c3ad9868
commit 5dc99cc137
1 changed files with 39 additions and 0 deletions
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39
src/chipset/sis_85c4xx.c
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@@ -15,6 +15,7 @@
*
* Copyright 2019-2020 Miran Grca.
*/
#include <math.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
@@ -631,6 +632,41 @@ sis_85c4xx_out(uint16_t port, uint8_t val, void *priv)
sis_85c4xx_recalcremap(dev);
break;
case 0x10:
if (dev->reg_base == 0x50) {
double bus_clk;
switch (val & 0xe0) {
default:
case 0x00:
bus_clk = 7159091.0;
break;
case 0x02:
bus_clk = cpu_busspeed / 10.0;
break;
case 0x04:
bus_clk = cpu_busspeed / 8.0;
break;
case 0x06:
bus_clk = cpu_busspeed / 6.0;
break;
case 0x80:
bus_clk = cpu_busspeed / 5.0;
break;
case 0xa0:
bus_clk = cpu_busspeed / 4.0;
break;
case 0xc0:
bus_clk = cpu_busspeed / 3.0;
break;
case 0xe0:
bus_clk = cpu_busspeed / 2.0;
break;
}
cpu_set_isa_speed((int) round(bus_clk));
}
break;
case 0x13:
if (dev->is_471 && (valxor & 0xf0)) {
smram_disable(dev->smram);
@@ -813,6 +849,9 @@ sis_85c4xx_reset(void *priv)
dev->force_flush = 1;
sis_85c4xx_recalcmapping(dev);
if (dev->reg_base == 0x50)
cpu_set_isa_speed((int) round(7159091.0));
}
static void