From 3a401af84e95480d9e79bd23fa6f5b009b474eb7 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Thu, 14 May 2020 01:36:52 +0200
Subject: [PATCH] Changes to update_tsc() - no longer requires a parameter and
 advances by all the currently accumulated cycles. Also changed TSC-related
 delta's to be correctly uint64_t.

---
 src/cpu_common/386_dynarec.c | 31 ++++++++++++++++++++++++-------
 src/cpu_common/cpu.h         |  2 +-
 src/io.c                     |  6 +++---
 3 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/src/cpu_common/386_dynarec.c b/src/cpu_common/386_dynarec.c
index f341efab9..af004521a 100644
--- a/src/cpu_common/386_dynarec.c
+++ b/src/cpu_common/386_dynarec.c
@@ -273,13 +273,28 @@ static void prefetch_flush()
 #define CACHE_ON() (!(cr0 & (1 << 30)) && !(cpu_state.flags & T_FLAG))
 
 #ifdef USE_DYNAREC
-static int cycles_main = 0;
+static int cycles_main = 0, cycles_old = 0;
+static uint64_t tsc_old = 0;
 
-void update_tsc(int cycs)
+void update_tsc(void)
 {
-    if (cycs > 0) {
-	tsc += cycs;
+    int cycdiff;
+    uint64_t delta;
 
+    cycdiff = cycles_old - cycles;
+    delta = tsc - tsc_old;
+    if (delta > 0) {
+	/* TSC has changed, this means interim timer processing has happened,
+	   see how much we still need to add. */
+	cycdiff -= delta;
+	if (cycdiff > 0)
+		tsc += cycdiff;
+    } else {
+	/* TSC has not changed. */
+	tsc += cycdiff;
+    }
+
+    if (cycdiff > 0) {
 	if (TIMER_VAL_LESS_THAN_VAL(timer_target, (uint32_t)tsc))
 		timer_process();
     }
@@ -291,9 +306,9 @@ void exec386_dynarec(int cycs)
 	uint32_t addr;
 	int tempi;
 	int cycdiff;
-	int oldcyc, oldtsc;
+	int oldcyc;
 	int oldcyc2;
-	int delta;
+	uint64_t oldtsc, delta;
 	uint32_t start_pc = 0;
 
 	int cyc_period = cycs / 2000; /*5us*/
@@ -317,7 +332,9 @@ void exec386_dynarec(int cycs)
 			cycdiff=0;
 #endif
 			oldcyc = oldcyc2 = cycles;
+			cycles_old = cycles;
 			oldtsc = tsc;
+			tsc_old = tsc;
 			if (!CACHE_ON()) /*Interpret block*/
 			{
 				cpu_block_end = 0;
@@ -723,7 +740,7 @@ void exec386_dynarec(int cycs)
 				/* TSC has not changed. */
 				tsc += cycdiff;
 			}
-		
+
 			if (cpu_state.abrt)
 			{
 				flags_rebuild();
diff --git a/src/cpu_common/cpu.h b/src/cpu_common/cpu.h
index 9129a7ab0..3a7d67d78 100644
--- a/src/cpu_common/cpu.h
+++ b/src/cpu_common/cpu.h
@@ -565,7 +565,7 @@ extern int	cpu_effective, cpu_alt_reset;
 extern void	cpu_dynamic_switch(int new_cpu);
 
 extern void	cpu_ven_reset(void);
-extern void	update_tsc(int cycs);
+extern void	update_tsc(void);
 
 extern int	sysenter(uint32_t fetchdat);
 extern int	sysexit(uint32_t fetchdat);
diff --git a/src/io.c b/src/io.c
index 89d341f76..fe356cfbf 100644
--- a/src/io.c
+++ b/src/io.c
@@ -331,7 +331,7 @@ outb(uint16_t port, uint8_t val)
     if (!found) {
 	sub_cycles(io_delay);
 	if (cpu_use_dynarec && (port == 0xeb))
-		update_tsc(io_delay);
+		update_tsc();
     }
 
     io_log("(%i, %i, %04i) outb(%04X, %02X)\n", in_smm, found, qfound, port, val);
@@ -424,7 +424,7 @@ outw(uint16_t port, uint16_t val)
     if (!found) {
 	sub_cycles(io_delay);
 	if (cpu_use_dynarec && (port == 0xeb))
-		update_tsc(io_delay);
+		update_tsc();
     }
 
     io_log("(%i, %i, %04i) outw(%04X, %04X)\n", in_smm, found, qfound, port, val);
@@ -551,7 +551,7 @@ outl(uint16_t port, uint32_t val)
     if (!found) {
 	sub_cycles(io_delay);
 	if (cpu_use_dynarec && (port == 0xeb))
-		update_tsc(io_delay);
+		update_tsc();
     }
 
     io_log("(%i, %i, %04i) outl(%04X, %08X)\n", in_smm, found, qfound, port, val);