SiS 5571, Daewoo Compaq, speed up AT / PS/2 KBC (does not appear to break anything from months of testing) and fix AT / PS/2 keyboard reset to fix the Samsung SPC7700LP-W soft reset.

src/cpu/cpu.c

@@ -181,6 +181,7 @@ int cpu_multi;
 int cpu_16bitbus;
 int cpu_64bitbus;
 int cpu_cyrix_alignment;
+int cpu_cpurst_on_sr;
 int CPUID;
 
 int is186;
@@ -742,6 +743,7 @@ cpu_set(void)
 
     timing_misaligned   = 0;
     cpu_cyrix_alignment = 0;
+    cpu_cpurst_on_sr    = 0;
     cpu_CR4_mask        = 0;
 
     switch (cpu_s->cpu_type) {
@@ -3018,6 +3020,10 @@ amd_k_invalid_rdmsr:
                     EAX = msr.ecx1002ff & 0xffffffff;
                     EDX = msr.ecx1002ff >> 32;
                     break;
+                case 0x40000020:
+                    EAX = msr.ecx40000020 & 0xffffffff;
+                    EDX = msr.ecx40000020 >> 32;
+                    break;
                 case 0xf0f00250:
                     EAX = msr.ecxf0f00250 & 0xffffffff;
                     EDX = msr.ecxf0f00250 >> 32;
@@ -3453,6 +3459,9 @@ amd_k_invalid_wrmsr:
                 case 0x1002ff:
                     msr.ecx1002ff = EAX | ((uint64_t) EDX << 32);
                     break;
+                case 0x40000020:
+                    msr.ecx40000020 = EAX | ((uint64_t) EDX << 32);
+                    break;
                 case 0xf0f00250:
                     msr.ecxf0f00250 = EAX | ((uint64_t) EDX << 32);
                     break;

src/cpu/cpu.h

@@ -339,6 +339,9 @@ typedef struct {
     /* K6-3, K6-2P, and K6-3P MSR's */
     uint64_t amd_l2aar; /* 0xc0000089 */
 
+    /* Weird long MSR's used by the Hyper-V BIOS. */
+    uint64_t ecx40000020; /* 0x40000020 */
+
     /* Pentium Pro, Pentium II Klamath, and Pentium II Deschutes MSR's */
     uint64_t ecxf0f00250; /* 0xf0f00250 - Some weird long MSR's used by i686 AMI & some Phoenix BIOSes */
     uint64_t ecxf0f00258; /* 0xf0f00258 */
@@ -544,8 +547,9 @@ extern int    cpu_multi;
 extern double cpu_dmulti;
 extern double fpu_multi;
 extern double cpu_busspeed;
-extern int    cpu_cyrix_alignment; /*Cyrix 5x86/6x86 only has data misalignment
-                                     penalties when crossing 8-byte boundaries*/
+extern int    cpu_cyrix_alignment; /* Cyrix 5x86/6x86 only has data misalignment
+                                      penalties when crossing 8-byte boundaries. */
+extern int    cpu_cpurst_on_sr;    /* SiS 551x and 5571: Issue CPURST on soft reset. */
 
 extern int is8086;
 extern int is186;

src/cpu/x86.c

@@ -342,6 +342,8 @@ reset_common(int hard)
 
     if (!is286)
         reset_808x(hard);
+
+    cpu_cpurst_on_sr = 0;
 }
 
 /* Hard reset. */