From 8514be287235f1cd1a3d033aaad34be9beb9b3a6 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Wed, 2 Mar 1994 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1994-03-02

---
 pc/clock.c     | 30 ++++++++++++++++++++++++++++++
 pc/fns.h       |  3 +++
 pc/l.s         | 24 +++++++++++++++++++++++-
 pc/main.c      | 11 ++++++++++-
 port/portfns.h |  2 +-
 5 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/pc/clock.c b/pc/clock.c
index 44afd132ad248dc145b96fe2f0e7deee0f266300..77a8a26dcf579720d26c9131bb598ea0c3824947 100644
--- a/pc/clock.c
+++ b/pc/clock.c
@@ -82,6 +82,36 @@ clock(Ureg *ur, void *arg)
 	splhi();
 }
 
+/*
+ *  experimentally determined and justified by counting cycles in
+ *  delay()'s inner loop
+ */
+enum
+{
+	mul386=	380,
+	mul486=	121,
+};
+
+void
+printcpufreq(void)
+{
+	ulong freq;
+	int cpu;
+
+	switch(cpu = x86()){
+	default:
+	case 486:
+		freq = mul486;
+		break;
+	case 386:
+		freq = mul386;
+		break;
+	}
+	freq *= delayloop;
+	freq /= 10000;
+	print("CPU is a %ud MHz %d\n", freq, cpu);
+}
+
 void
 clockinit(void)
 {
diff --git a/pc/fns.h b/pc/fns.h
index 2456e2f260849b864417e88f11a1ddc61b6605aa..f6781646a281de981fadc9569848370dc6c88c71 100644
--- a/pc/fns.h
+++ b/pc/fns.h
@@ -66,6 +66,7 @@ void	pcmspecialclose(int);
 long	pcmwrite(int, int, void*, long, ulong);
 void	prflush(void);
 void	prhex(ulong);
+void	printcpufreq(void);
 void	procrestore(Proc*);
 void	procsave(Proc*);
 void	procsetup(Proc*);
@@ -86,6 +87,8 @@ void	trapinit(void);
 int	tas(void*);
 void	uartclock(void);
 void	vgainit(void);
+int	x86(void);
+
 #define	waserror()	(up->nerrlab++, setlabel(&up->errlab[up->nerrlab-1]))
 #define	kmapperm(x)	kmap(x)
 #define getcallerpc(x)	(*(ulong*)(x))
diff --git a/pc/l.s b/pc/l.s
index 97be6af82bd1080ccf975d4e914a97d4504797a1..5d234639623136e63a26aa6f017c6372bca550e2 100644
--- a/pc/l.s
+++ b/pc/l.s
@@ -54,7 +54,7 @@ setpte:
 	MOVL	AX,CR3
 	MOVL	CR0,AX
 	ORL	$0X80010000,AX
-	ANDL	$~(0x8|0x2),AX	/* TS=0, MP=0 */
+	ANDL	$~(0x40000000|0x20000000|0x8|0x2),AX	/* CD=0, NW=0, TS=0, MP=0 */
 	MOVL	AX,CR0
 
 	/*
@@ -566,6 +566,28 @@ TEXT	idle(SB),$0
 	HLT
 	RET
 
+/*
+ *  return cpu type (what is a pentium?)
+ */
+TEXT	x86(SB),$0
+
+	PUSHFL
+	MOVL	0(SP),AX
+	ORL	$0x40000,AX
+	PUSHL	AX
+	POPFL
+	PUSHFL
+	POPL	AX
+	ANDL	$0x40000,AX
+	JZ	is386
+	MOVL	$486,AX
+	JMP	done
+is386:
+	MOVL	$386,AX
+done:
+	POPFL
+	RET
+
 /*
  *  label consists of a stack pointer and a PC
  */
diff --git a/pc/main.c b/pc/main.c
index 1dee5f733cc2ec8b7bb63d43364cf1469986a66b..715b47dc3e7d40501373dddcd4954af1721ac82e 100644
--- a/pc/main.c
+++ b/pc/main.c
@@ -58,6 +58,7 @@ main(void)
 	procinit0();
 	initseg();
 	links();
+	printcpufreq();
 	chandevreset();
 	swapinit();
 	userinit();
@@ -391,7 +392,15 @@ confinit(void)
 	conf.monitor = 1;
 	conf.nswap = conf.nproc*80;
 	conf.nimage = 50;
-	conf.copymode = 0;			/* copy on write */
+	switch(x86()){
+	case 386:
+		conf.copymode = 1;	/* copy on reference */
+		break;
+	default:
+	case 486:
+		conf.copymode = 0;	/* copy on write */
+		break;
+	}
 	conf.nfloppy = 2;
 	conf.nhard = 2;
 	conf.nmach = 1;
diff --git a/port/portfns.h b/port/portfns.h
index 723a2fb42f3a5893b1b9e642c1fe9ea833c6abe6..3779b8eb45c3c4b25bd8af6c12791f3ab82eea23 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -218,7 +218,7 @@ void		sched(void);
 void		schedinit(void);
 int		screenbits(void);
 void		screenupdate(void);
-int		scsiexec(Target*, int, uchar*, int, void*, int);
+int		scsiexec(Target*, int, uchar*, int, void*, int*);
 int		scsiinv(int, int, Target**, uchar**, char*);
 Target*		scsiunit(int, int);
 long		seconds(void);