X-Git-Url: http://git.subgeniuskitty.com/pdp11-modern-c/.git/blobdiff_plain/846f4d60e4994a39decd6c27463411f53965fc60..202004d54803c861f7fbaa9169eaad750c63f7cf:/pdp11/interrupt_handler.s

diff --git a/pdp11/interrupt_handler.s b/pdp11/interrupt_handler.s
new file mode 100644
index 0000000..970363b
--- /dev/null
+++ b/pdp11/interrupt_handler.s
@@ -0,0 +1,24 @@
+# (c) 2020 Aaron Taylor <ataylor at subgeniuskitty dot com>
+# See License.txt file for copyright and license details.
+
+.globl _int4_asm_handler
+.globl _int4_c_handler
+
+_int4_asm_handler:
+    # GCC appears to be using the same calling convention documented in the
+    # original UNIX manuals. Most of these register saves are probably
+    # unnecessary.
+    mov r0,-(sp)
+    mov r1,-(sp)
+    mov r2,-(sp)
+    mov r3,-(sp)
+    mov r4,-(sp)
+    mov r5,-(sp)
+    jsr pc, _int4_c_handler
+    mov (sp)+,r5
+    mov (sp)+,r4
+    mov (sp)+,r3
+    mov (sp)+,r2
+    mov (sp)+,r1
+    mov (sp)+,r0
+    rti