Add custom ISA/PCI/AGP clock facility, and fix PIT clock calculation oversight for CPU clocks ending in (but not equal to) 33 and 66 MHz

src/cpu/cpu.c

@@ -167,7 +167,7 @@ int		cpu_prefetch_cycles, cpu_prefetch_width,
 		cpu_mem_prefetch_cycles, cpu_rom_prefetch_cycles;
 int		cpu_waitstates;
 int		cpu_cache_int_enabled, cpu_cache_ext_enabled;
-int		cpu_pci_speed, cpu_alt_reset;
+int		cpu_isa_speed, cpu_pci_speed, cpu_isa_pci_div, cpu_agp_speed, cpu_alt_reset;
 uint16_t	cpu_fast_off_count, cpu_fast_off_val;
 uint32_t	cpu_fast_off_flags;
 int		is_vpc;
@@ -571,15 +571,9 @@ cpu_set(void)
         else
                 cpu_rom_prefetch_cycles = cpu_s->rspeed / 1000000;
 
-	if (cpu_busspeed < 42500000)
+        cpu_set_isa_pci_div(0);
-		cpu_pci_speed = cpu_busspeed;
+        cpu_set_pci_speed(0);
-	else if ((cpu_busspeed > 42500000) && (cpu_busspeed < 84000000))
+        cpu_set_agp_speed(0);
-		cpu_pci_speed = cpu_busspeed / 2;
-	else
-		cpu_pci_speed = cpu_busspeed / 3;
-
-	pci_burst_time = cpu_s->rspeed / cpu_pci_speed;
-	pci_nonburst_time = 4 * pci_burst_time;
 
         if (cpu_iscyrix)
 		io_sethandler(0x0022, 0x0002, cpu_read, NULL, NULL, cpu_write, NULL, NULL, NULL);
@@ -1879,6 +1873,82 @@ cpu_set(void)
 		x87_timings = x87_timings_486;
 	}
 }
+
+
+void
+cpu_set_isa_speed(int speed)
+{
+    if (speed) {
+	cpu_isa_speed = speed;
+	pc_speed_changed();
+    } else
+	cpu_isa_speed = 8000000;
+
+    cpu_log("cpu_set_isa_speed(%d) = %d\n", speed, cpu_isa_speed);
+}
+
+
+void
+cpu_set_pci_speed(int speed)
+{
+    if (speed)
+	cpu_pci_speed = speed;
+    else if (cpu_busspeed < 42500000)
+	cpu_pci_speed = cpu_busspeed;
+    else if (cpu_busspeed < 84000000)
+	cpu_pci_speed = cpu_busspeed / 2;
+    else if (cpu_busspeed < 120000000)
+	cpu_pci_speed = cpu_busspeed / 3;
+    else
+	cpu_pci_speed = cpu_busspeed / 4;
+
+    if (cpu_isa_pci_div)
+	cpu_set_isa_pci_div(cpu_isa_pci_div);
+    else if (speed)
+	pc_speed_changed();
+
+    pci_burst_time = cpu_s->rspeed / cpu_pci_speed;
+    pci_nonburst_time = 4 * pci_burst_time;
+
+    cpu_log("cpu_set_pci_speed(%d) = %d\n", speed, cpu_pci_speed);
+}
+
+
+void
+cpu_set_isa_pci_div(int div)
+{
+    cpu_isa_pci_div = div;
+
+    cpu_log("cpu_set_isa_pci_div(%d)\n", cpu_isa_pci_div);
+
+    if (cpu_isa_pci_div)
+	cpu_set_isa_speed(cpu_pci_speed / cpu_isa_pci_div);
+    else
+	cpu_set_isa_speed(0);
+}
+
+
+void
+cpu_set_agp_speed(int speed)
+{
+    if (speed) {
+	cpu_agp_speed = speed;
+	pc_speed_changed();
+    }
+    else if (cpu_busspeed < 84000000)
+	cpu_agp_speed = cpu_busspeed;
+    else if (cpu_busspeed < 120000000)
+	cpu_agp_speed = cpu_busspeed / 1.5;
+    else
+	cpu_agp_speed = cpu_busspeed / 2;
+
+    agp_burst_time = cpu_s->rspeed / cpu_agp_speed;
+    agp_nonburst_time = 4 * agp_burst_time;
+
+    cpu_log("cpu_set_agp_speed(%d) = %d\n", speed, cpu_agp_speed);
+}
+
+
 char *
 cpu_current_pc(char *bufp)
 {

src/cpu/cpu.h

@@ -433,7 +433,7 @@ extern uint32_t		oldds,oldss,olddslimit,oldsslimit,olddslimitw,oldsslimitw;
 extern uint32_t		pccache;
 extern uint8_t		*pccache2;
 
-extern double		bus_timing, pci_timing;
+extern double		bus_timing, isa_timing, pci_timing, agp_timing;
 extern uint64_t		pmc[2];
 extern uint16_t		temp_seg_data[4];
 extern uint16_t		cs_msr;
@@ -477,7 +477,7 @@ extern int	cpu_cycles_read, cpu_cycles_read_l, cpu_cycles_write, cpu_cycles_writ
 extern int	cpu_prefetch_cycles, cpu_prefetch_width, cpu_mem_prefetch_cycles, cpu_rom_prefetch_cycles;
 extern int	cpu_waitstates;
 extern int	cpu_cache_int_enabled, cpu_cache_ext_enabled;
-extern int	cpu_pci_speed;
+extern int	cpu_isa_speed, cpu_pci_speed, cpu_agp_speed;
 
 extern int	timing_rr;
 extern int	timing_mr, timing_mrl;
@@ -523,6 +523,10 @@ extern char	*cpu_current_pc(char *bufp);
 
 extern void	cpu_update_waitstates(void);
 extern void	cpu_set(void);
+extern void	cpu_set_isa_speed(int speed);
+extern void	cpu_set_pci_speed(int speed);
+extern void	cpu_set_isa_pci_div(int div);
+extern void	cpu_set_agp_speed(int speed);
 
 extern void	cpu_CPUID(void);
 extern void	cpu_RDMSR(void);

src/include/86box/pit.h

@@ -49,7 +49,7 @@ typedef struct PIT {
 extern pit_t	*pit,
 		*pit2;
 
-extern double	SYSCLK, PCICLK;
+extern double	SYSCLK, PCICLK, AGPCLK;
 
 extern uint64_t	PITCONST, ISACONST,
 		CGACONST,

src/pit.c

@@ -44,8 +44,8 @@ pit_t		*pit, *pit2;
 double		cpuclock, PITCONSTD,
 		SYSCLK,
 		isa_timing,
-		bus_timing, pci_timing,
+		bus_timing, pci_timing, agp_timing,
-		PCICLK;
+		PCICLK, AGPCLK;
 
 uint64_t	PITCONST, ISACONST,
 		CGACONST,
@@ -961,17 +961,18 @@ pit_set_clock(int clock)
 {
     /* Set default CPU/crystal clock and xt_cpu_multi. */
     if (cpu_s->cpu_type >= CPU_286) {
-	if (clock == 66666666)
+	int remainder = (clock % 100000000);
-		cpuclock = 200000000.0 / 3.0;
+	if (remainder == 66666666)
-	else if (clock == 33333333)
+		cpuclock = (double) (clock - remainder) + (200000000.0 / 3.0);
-		cpuclock = 100000000.0 / 3.0;
+	else if (remainder == 33333333)
+		cpuclock = (double) (clock - remainder) + (100000000.0 / 3.0);
 	else
 		cpuclock = (double) clock;
 
 	PITCONSTD = (cpuclock / 1193182.0);
 	PITCONST = (uint64_t) (PITCONSTD * (double)(1ull << 32));
 	CGACONST = (uint64_t) ((cpuclock / (19687503.0/11.0)) * (double)(1ull << 32));
-	ISACONST = (uint64_t) ((cpuclock / 8000000.0) * (double)(1ull << 32));
+	ISACONST = (uint64_t) ((cpuclock / (double)cpu_isa_speed) * (double)(1ull << 32));
 	xt_cpu_multi = 1ULL;
     } else {
 	cpuclock = 14318184.0;
@@ -1039,15 +1040,17 @@ pit_set_clock(int clock)
 
     TIMER_USEC = (uint64_t)((cpuclock / 1000000.0) * (double)(1ull << 32));
 
-    isa_timing = (cpuclock / (double)8000000.0);
+    isa_timing = (cpuclock / (double)cpu_isa_speed);
     if (cpu_64bitbus)
 	bus_timing = (cpuclock / ((double)cpu_busspeed / 2));
     else
 	bus_timing = (cpuclock / (double)cpu_busspeed);	    
     pci_timing = (cpuclock / (double)cpu_pci_speed);
+    agp_timing = (cpuclock / (double)cpu_agp_speed);
 
     /* PCICLK in us for use with timer_on_auto(). */
     PCICLK = pci_timing / (cpuclock / 1000000.0);
+    AGPCLK = agp_timing / (cpuclock / 1000000.0);
 
     if (cpu_busspeed >= 30000000)
 	SYSCLK = bus_timing * 4.0;