pdp11/interrupt_handler.s

# (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