gdb/testsuite/gdb.arch/arc-dbnz.exp

# This testcase is part of GDB, the GNU debugger.

# Copyright 2024 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
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# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Test dbnz instruction. It decrements its source register operand, and if
# the result is non-zero it branches to the location defined by a signed
# half-word displacement operand.
#
# It's necessary to verify these cases:
#
#     1. Check that dbnz does not branch and falls through if its source
#        register is 0 after decrementing. GDB must successfully break
#        on the following instruction after stepping over.
#     2. Check that dbnz branches to the target correctly if its source register
#        is not 0 after decrementing - GDB must successfully break on the target
#        instruction if a forward branch is performed after stepping over.
#     3. The same as point 2 but for a backward branching case.

require {istarget "arc*-*-*"}

standard_testfile .S

if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
    return -1
}

if ![runto_main] {
    return 0
}

gdb_test "break dbnz1" \
	 "Breakpoint $decimal at .*" \
	 "set breakpoint on the 1st dbnz"

gdb_test "break dbnz2" \
	 "Breakpoint $decimal at .*" \
	 "set breakpoint on the 2nd dbnz"

gdb_test "break dbnz3" \
	 "Breakpoint $decimal at .*" \
	 "set breakpoint on the 3rd dbnz"

gdb_test "break dbnz4" \
	 "Breakpoint $decimal at .*" \
	 "set breakpoint on the 4th dbnz"

gdb_test "break end" \
	 "Breakpoint $decimal at .*" \
	 "set breakpoint at the end"

gdb_test "continue" \
	 "Breakpoint $decimal, dbnz1.*dbnz r0,@end" \
	 "continue to the 1st dbnz"

gdb_test "x /i \$pc" \
	 "$hex <.*>:\[ \t\]+dbnz\[ \t\]+r0,24.*" \
	 "stayng on the 1st dbnz instruction"

gdb_test "stepi" \
	 "mov r0,5" \
	 "step over the 1st dbnz, branch is not taken"

gdb_test "stepi" \
	 "Breakpoint $decimal, dbnz2.*dbnz\\.d r0,@dbnz3" \
	 "step over r0 initialization, staying on the 2nd dbnz"

# Linux steps over delay slot after "stepi", but stubs with hardware stepping
# like nSIM's stub may step right on delay slot. Thus use "continue" instead of
# "stepi" to make this test work for all platforms.
gdb_test "continue" \
	 "Breakpoint $decimal, dbnz3.*dbnz r0,@dbnz4" \
	 "step over the 2nd dbnz, branch is taken, staying on the 3rd dbnz"

gdb_test "stepi" \
	 "Breakpoint $decimal, dbnz4.*dbnz r0,@end" \
	 "step over the 3rd dbnz, branch is taken, staying on the 4th dbnz"

gdb_test "stepi" \
	 "Breakpoint $decimal, end.*mov r0,0" \
	 "step over the 4th dbnz, branch is taken, staying on the epilogue"

gdb_test "info register r0" \
	 "r0\[ \t\]+0x1\[ \t\]+1" \
	 "r0 contains 1 after all dbnz instructions"