From c8939dc6464bc4d38c425e7e655a11ce2322179d Mon Sep 17 00:00:00 2001
From: Serge Vakulenko <serge.vakulenko@gmail.com>
Date: Thu, 20 Aug 2015 20:55:55 -0700
Subject: [PATCH] Fix bug in assembler: incorrect reordering of branch
 instruction. Increase cpp buffer size.

---
 src/cmd/as/as.c           |  8 ++++++++
 src/cmd/as/tests/Makefile |  8 ++++----
 src/cmd/as/tests/test5.s  | 26 ++++++++++++++++++++++++++
 src/cmd/cpp/cpp.h         |  8 ++++----
 4 files changed, 42 insertions(+), 8 deletions(-)
 create mode 100644 src/cmd/as/tests/test5.s

diff --git a/src/cmd/as/as.c b/src/cmd/as/as.c
index f63e80a..13792f2 100644
--- a/src/cmd/as/as.c
+++ b/src/cmd/as/as.c
@@ -1721,6 +1721,14 @@ done:
                 ((type & FRT2) && rt == reorder_clobber))
                 reorder_flush();
         }
+        if (reorder_full && (type & (FOFF18 | FAOFF18)) &&
+            relinfo.flags == RABS && (opcode & 0x8000)) {
+            /* Branch instruction with negative offset is being displaced
+             * by one word.  Need to update the offset field. */
+            offset = opcode + 1;
+            opcode &= ~0xffff;
+            opcode |= (offset & 0xffff);
+        }
         fputword (opcode, sfile[segm]);
         fputrel (&relinfo, rfile[segm]);
         if (reorder_full) {
diff --git a/src/cmd/as/tests/Makefile b/src/cmd/as/tests/Makefile
index 2a7d529..ae670f5 100644
--- a/src/cmd/as/tests/Makefile
+++ b/src/cmd/as/tests/Makefile
@@ -2,14 +2,14 @@ TOPSRC		= $(shell cd ../../../..; pwd)
 include $(TOPSRC)/target.mk
 
 CFLAGS		+= -Wall -Os
-TESTS           = test1 test2 test3 test4
+TESTS           = test1 test2 test3 test4 test5
 
-all:            ../as ../aout
+all:            ../../../../lib/as ../../../../lib/aout
 		for i in $(TESTS); do \
                     $(AS) $$i.s -o $$i.o; \
                     $(OBJDUMP) -D $$i.o > $$i.gcc-dis; \
-                    ../as $$i.s -o $$i.o; \
-                    ../aout -r $$i.o > $$i.dis; \
+                    ../../../../lib/as $$i.s -o $$i.o; \
+                    ../../../../lib/aout -r $$i.o > $$i.dis; \
                 done
 
 clean:
diff --git a/src/cmd/as/tests/test5.s b/src/cmd/as/tests/test5.s
new file mode 100644
index 0000000..2ec3c39
--- /dev/null
+++ b/src/cmd/as/tests/test5.s
@@ -0,0 +1,26 @@
+        .set    reorder
+x:
+        add     $2, $16, $31
+        b       x
+        sub	$31, $11, $26
+
+        add     $2, $16, $31
+        beqz    $3, x
+        sub	$31, $11, $26
+
+        add     $2, $16, $31
+        j       x
+        sub	$31, $11, $26
+
+        and     $31, $3, $18
+        b       y
+        or	$31, $8, $23
+
+        and     $31, $3, $18
+        beqz    $2, y
+        or	$31, $8, $23
+
+        and     $31, $3, $18
+        j       y
+        or	$31, $8, $23
+y:
diff --git a/src/cmd/cpp/cpp.h b/src/cmd/cpp/cpp.h
index bebc226..66c1ccd 100644
--- a/src/cmd/cpp/cpp.h
+++ b/src/cmd/cpp/cpp.h
@@ -48,7 +48,7 @@ extern	int	ofd;
 #define ENTER   1
 
 /* buffer used internally */
-#define CPPBUF	512
+#define CPPBUF	640
 #ifndef CPPBUF
 #if defined(__pdp11__)
 #define CPPBUF  BUFSIZ
@@ -86,7 +86,7 @@ extern int bidx;
 #define C_SPEC	001
 #define C_EP	002
 #define C_ID	004
-#define C_I	(C_SPEC|C_ID)		
+#define C_I	(C_SPEC|C_ID)
 #define C_2	010		/* for yylex() tokenizing */
 #define	C_WSNL	020		/* ' ','\t','\r','\n' */
 #define	iswsnl(x) (spechr[x] & C_WSNL)
@@ -116,8 +116,8 @@ extern struct includ *ifiles;
 
 /* Symbol table entry  */
 struct symtab {
-	const usch *namep;    
-	const usch *value;    
+	const usch *namep;
+	const usch *value;
 	const usch *file;
 	int line;
 };