[PATCH, repost] Add a dummy interrupt handler to nios2 crt0.s.

[Sandra Loosemore]

The location of the handler at offset 0x20 from the start of memory,
immediately after the 32-byte reset vector, matches the expectations
of real hardware (e.g., a 3c120 board).
---
 libgloss/nios2/crt0.S | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/libgloss/nios2/crt0.S b/libgloss/nios2/crt0.S
index 77eacb3..c4dd4c6 100644
--- a/libgloss/nios2/crt0.S
+++ b/libgloss/nios2/crt0.S
@@ -1,6 +1,6 @@
 /* crt0.S -- startup code for Nios II QEMU generic-nommu board emulation.
 
-   Copyright (c) 2018 Mentor Graphics
+   Copyright (c) 2018-2019 Mentor Graphics
 
    The authors hereby grant permission to use, copy, modify, distribute,
    and license this software and its documentation for any purpose, provided
@@ -81,6 +81,18 @@ __reset:
 
 	.size __reset, . - __reset
 
+/* Provide a stub interrupt handler that waits in a busy loop.
+   The alignment puts it at offset 0x20 from the base of RAM.  */
+
+	.align 5
+
+        .globl  __interrupt_handler
+        .type   __interrupt_handler, @function
+__interrupt_handler:
+0:
+	br 0b
+
+	.size __interrupt_handler, . - __interrupt_handler
 
 /* __start is the ELF entry point.  */
 
-- 
2.8.1