From c9172fb2a3fed51646897d0107c304f48a6cdbe3 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Mon, 14 Jun 2010 18:07:17 -0700
Subject: [PATCH] runtime: correct fault for 16-bit divide on Leopard

R=r
CC=golang-dev
https://golang.org/cl/1703041
---
 src/pkg/runtime/darwin/386/signal.c   |  4 +++-
 src/pkg/runtime/darwin/amd64/signal.c |  4 +++-
 test/golden.out                       |  4 ----
 test/zerodivide.go                    | 12 ++++--------
 4 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/src/pkg/runtime/darwin/386/signal.c b/src/pkg/runtime/darwin/386/signal.c
index 7c0c381d37..b4af42bb4f 100644
--- a/src/pkg/runtime/darwin/386/signal.c
+++ b/src/pkg/runtime/darwin/386/signal.c
@@ -54,7 +54,9 @@ sighandler(int32 sig, Siginfo *info, void *context)
 		// Not necessary in Snow Leopard (si_code will be != 0).
 		if(sig == SIGFPE && info->si_code == 0) {
 			pc = (byte*)r->eip;
-			if(pc[0] == 0xF7)
+			if(pc[0] == 0x66)	// 16-bit instruction prefix
+				pc++;
+			if(pc[0] == 0xF6 || pc[0] == 0xF7)
 				info->si_code = FPE_INTDIV;
 		}
 		
diff --git a/src/pkg/runtime/darwin/amd64/signal.c b/src/pkg/runtime/darwin/amd64/signal.c
index 8145e8d8f4..b3fa8404f1 100644
--- a/src/pkg/runtime/darwin/amd64/signal.c
+++ b/src/pkg/runtime/darwin/amd64/signal.c
@@ -63,7 +63,9 @@ sighandler(int32 sig, Siginfo *info, void *context)
 			pc = (byte*)r->rip;
 			if((pc[0]&0xF0) == 0x40)	// 64-bit REX prefix
 				pc++;
-			if(pc[0] == 0xF7)
+			else if(pc[0] == 0x66)	// 16-bit instruction prefix
+				pc++;
+			if(pc[0] == 0xF6 || pc[0] == 0xF7)
 				info->si_code = FPE_INTDIV;
 		}
 		
diff --git a/test/golden.out b/test/golden.out
index d6d9d576a1..24e24a28e1 100644
--- a/test/golden.out
+++ b/test/golden.out
@@ -54,10 +54,6 @@ FAIL
 Hello World!
 
 =========== ./zerodivide.go
-int16 0/0: expected "divide"; got "runtime error: floating point error"
-int16 1/0: expected "divide"; got "runtime error: floating point error"
-uint16 0/0: expected "divide"; got "runtime error: floating point error"
-uint16 1/0: expected "divide"; got "runtime error: floating point error"
 complex 0/0: expected no error; got "runtime error: complex divide by zero"
 complex64 0/0: expected no error; got "runtime error: complex divide by zero"
 complex128 0/0: expected no error; got "runtime error: complex divide by zero"
diff --git a/test/zerodivide.go b/test/zerodivide.go
index 38a040ade6..948aedd930 100644
--- a/test/zerodivide.go
+++ b/test/zerodivide.go
@@ -56,30 +56,26 @@ func use(v interface{}) {
 var errorTests = []ErrorTest{
 	// All integer divide by zero should error.
 	ErrorTest{ "int 0/0", func() { use(i/j) }, "divide", },
-// TODO commented out: fails in 8g.
-//	ErrorTest{ "int8 0/0", func() { use(i8/j8) }, "divide", },
+	ErrorTest{ "int8 0/0", func() { use(i8/j8) }, "divide", },
 	ErrorTest{ "int16 0/0", func() { use(i16/j16) }, "divide", },
 	ErrorTest{ "int32 0/0", func() { use(i32/j32) }, "divide", },
 	ErrorTest{ "int64 0/0", func() { use(i64/j64) }, "divide", },
 
 	ErrorTest{ "int 1/0", func() { use(k/j) }, "divide", },
-// TODO commented out: fails in 8g.
-//	ErrorTest{ "int8 1/0", func() { use(k8/j8) }, "divide", },
+	ErrorTest{ "int8 1/0", func() { use(k8/j8) }, "divide", },
 	ErrorTest{ "int16 1/0", func() { use(k16/j16) }, "divide", },
 	ErrorTest{ "int32 1/0", func() { use(k32/j32) }, "divide", },
 	ErrorTest{ "int64 1/0", func() { use(k64/j64) }, "divide", },
 
 	ErrorTest{ "uint 0/0", func() { use(u/v) }, "divide", },
-// TODO commented out: fails in 8g.
-//	ErrorTest{ "uint8 0/0", func() { use(u8/v8) }, "divide", },
+	ErrorTest{ "uint8 0/0", func() { use(u8/v8) }, "divide", },
 	ErrorTest{ "uint16 0/0", func() { use(u16/v16) }, "divide", },
 	ErrorTest{ "uint32 0/0", func() { use(u32/v32) }, "divide", },
 	ErrorTest{ "uint64 0/0", func() { use(u64/v64) }, "divide", },
 	ErrorTest{ "uintptr 0/0", func() { use(up/vp) }, "divide", },
 
 	ErrorTest{ "uint 1/0", func() { use(w/v) }, "divide", },
-// TODO commented out: fails in 8g.
-//	ErrorTest{ "uint8 1/0", func() { use(w8/v8) }, "divide", },
+	ErrorTest{ "uint8 1/0", func() { use(w8/v8) }, "divide", },
 	ErrorTest{ "uint16 1/0", func() { use(w16/v16) }, "divide", },
 	ErrorTest{ "uint32 1/0", func() { use(w32/v32) }, "divide", },
 	ErrorTest{ "uint64 1/0", func() { use(w64/v64) }, "divide", },
-- 
2.50.0