433730c973
Consider the following simple program:
.globl _start
.text
_start:
fldt val
.data
val: .byte 0x00,0x00,0x45,0x07,0x11,0x19,0x22,0xe9,0xfe,0xbf
With current GDB on x86-64 GNU/Linux hosts, after the moment the fldt
command has been executed the register st(0) looks like this,
according to the “info regs” output (TOP=7):
R7: Valid 0xffffffbffffffffeffffffe922191107450000 -0.910676542908976927
which is clearly wrong (just count its length). The problem is due to
the printf statement (see patch) printing a promoted integer value of
a char argument "raw[i]", and, since char is signed on x86-64
GNU/Linux, the erroneous “ffffff” are printed for the first three
bytes which turn out to be "negative". The fix is to use gdb_byte
instead which is unsigned (and is the type of value_contents(), the
type to be used for raw target bytes anyway). After the fix the value
will be printed correctly:
R7: Valid 0xbffee922191107450000 -0.910676542908976927
gdb/
2013-04-19 Vladimir Kargov <kargov@gmail.com>
Pedro Alves <palves@redhat.com>
* i387-tdep.c (i387_print_float_info): Use gdb_byte for pointer to
value contents.
gdb/testsuite/
2013-04-19 Vladimir Kargov <kargov@gmail.com>
Pedro Alves <palves@redhat.com>
* gdb.arch/i386-float.S: New file.
* gdb.arch/i386-float.exp: New file.
43 lines
1.4 KiB
Text
43 lines
1.4 KiB
Text
# Copyright (C) 2009-2013 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# This file is part of the gdb testsuite.
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# Test the x87 floating point information printout.
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if { ![istarget "i?86-*-*"] && ![istarget "x86_64-*-*"] } then {
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verbose "Skipping i386 tests for x87 floating point support."
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return
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}
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standard_testfile .S
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# some targets have leading underscores on assembly symbols.
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set additional_flags [gdb_target_symbol_prefix_flags]
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if { [prepare_for_testing break.exp $testfile $srcfile [list debug $additional_flags]] } {
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return -1
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}
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if ![runto_main] then {
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fail "Can't run to main"
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return 0
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}
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gdb_test "stepi" ".*fldt.*" "first stepi"
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gdb_test "info float" ".*R7: Empty 0x00000000000000000000\r\n.*"
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gdb_test "stepi" ".*ret.*" "second stepi"
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gdb_test "info float" ".*=>R7: Valid 0xbffee922191107450000 .*"
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