From 3ba213a9d79bfe52f9a8aa6834c67eac665de136 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@gmx.de>
Date: Tue, 18 Sep 2012 18:18:43 +0200
Subject: 6c: extern register fix (import from patch/6c-extreg)

to make it easy to use normal libraries (such as libdraw, libsec, and libmp)
with the kernel, which uses extern register, don't stray into the external
register set when allocating values to registers.
---
 amd64/include/u.h     |  2 +-
 sys/src/cmd/6c/reg.c  |  2 ++
 sys/src/cmd/6c/txt.c  | 17 ++++++++++++-----
 sys/src/cmd/6l/span.c |  3 +++
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/amd64/include/u.h b/amd64/include/u.h
index feb121703..8dce5066f 100644
--- a/amd64/include/u.h
+++ b/amd64/include/u.h
@@ -10,7 +10,7 @@ typedef unsigned long long uintptr;
 typedef unsigned long	usize;
 typedef	ushort		Rune;
 typedef union FPdbleword FPdbleword;
-typedef uvlong		jmp_buf[2];
+typedef uintptr		jmp_buf[2];
 #define	JMPBUFSP	0
 #define	JMPBUFPC	1
 #define	JMPBUFDPC	0
diff --git a/sys/src/cmd/6c/reg.c b/sys/src/cmd/6c/reg.c
index 32b9abf5d..43e21a4f3 100644
--- a/sys/src/cmd/6c/reg.c
+++ b/sys/src/cmd/6c/reg.c
@@ -50,6 +50,8 @@ regopt(Prog *p)
 	lastr = R;
 	nvar = 0;
 	regbits = RtoB(D_SP) | RtoB(D_AX) | RtoB(D_X0);
+	if(REGEXT)
+		regbits |= RtoB(REGEXT) | RtoB(REGEXT-1);
 	for(z=0; z<BITS; z++) {
 		externs.b[z] = 0;
 		params.b[z] = 0;
diff --git a/sys/src/cmd/6c/txt.c b/sys/src/cmd/6c/txt.c
index 24ac1db46..e3b9a9ee5 100644
--- a/sys/src/cmd/6c/txt.c
+++ b/sys/src/cmd/6c/txt.c
@@ -1,5 +1,7 @@
 #include "gc.h"
 
+static	int	resvreg[nelem(reg)];
+
 void
 ginit(void)
 {
@@ -94,6 +96,7 @@ ginit(void)
 	if(0)
 		com64init();
 
+	memset(reg, 0, sizeof(reg));
 	for(i=0; i<nelem(reg); i++) {
 		reg[i] = 1;
 		if(i >= D_AX && i <= D_R15 && i != D_SP)
@@ -101,6 +104,10 @@ ginit(void)
 		if(i >= D_X0 && i <= D_X7)
 			reg[i] = 0;
 	}
+	/* keep two external registers */
+	reg[REGEXT] = 1;
+	reg[REGEXT-1] = 1;
+	memmove(resvreg, reg, sizeof(resvreg));
 }
 
 void
@@ -111,10 +118,10 @@ gclean(void)
 
 	reg[D_SP]--;
 	for(i=D_AX; i<=D_R15; i++)
-		if(reg[i])
+		if(reg[i] && !resvreg[i])
 			diag(Z, "reg %R left allocated", i);
 	for(i=D_X0; i<=D_X7; i++)
-		if(reg[i])
+		if(reg[i] && !resvreg[i])
 			diag(Z, "reg %R left allocated", i);
 	while(mnstring)
 		outstring("", 1L);
@@ -179,7 +186,7 @@ nareg(void)
 
 	n = 0;
 	for(i=D_AX; i<=D_R15; i++)
-		if(reg[i] == 0)
+		if(reg[i] == 0 && !resvreg[i])
 			n++;
 	return n;
 }
@@ -337,7 +344,7 @@ regalloc(Node *n, Node *tn, Node *o)
 				goto out;
 		}
 		for(i=D_AX; i<=D_R15; i++)
-			if(reg[i] == 0)
+			if(reg[i] == 0 && !resvreg[i])
 				goto out;
 		diag(tn, "out of fixed registers");
 		goto err;
@@ -350,7 +357,7 @@ regalloc(Node *n, Node *tn, Node *o)
 				goto out;
 		}
 		for(i=D_X0; i<=D_X7; i++)
-			if(reg[i] == 0)
+			if(reg[i] == 0 && !resvreg[i])
 				goto out;
 		diag(tn, "out of float registers");
 		goto out;
diff --git a/sys/src/cmd/6l/span.c b/sys/src/cmd/6l/span.c
index 78399a2b3..ec36e1490 100644
--- a/sys/src/cmd/6l/span.c
+++ b/sys/src/cmd/6l/span.c
@@ -668,6 +668,9 @@ asmandsz(Adr *a, int r, int rex, int m64)
 
 	rex &= (0x40 | Rxr);
 	v = a->offset;
+	if ((vlong)v != a->offset) 
+		print("asmandsz: Trying to emit %#ullx and 32 bits is not sufficient\n",
+			a->offset);
 	t = a->type;
 	if(a->index != D_NONE) {
 		if(t >= D_INDIR) {
-- 
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