Despite them being ignored by the CPU, gas issues segment override

prefixes for other than FS/GS in 64-bit mode. If doing so at all, it
should clearly do this correctly. Determining the default segment,
however, requires to take into consideration RegRex (so far, RSP, RBP,
R12, and R13 were all treated equally here).

gas/
2012-08-07  Jan Beulich <jbeulich@suse.com>

	* config/tc-i386-intel.c (build_modrm_byte): Split determining
	default segment from figuring out encoding. Honor RegRex for
	the former.

gas/testsuite/
2012-08-07  Jan Beulich <jbeulich@suse.com>

	* gas/i386/x86-64-segovr.{s,l}: New.
	* gas/i386/i386.exp: Run new test.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 2c6dfd2296cbb08809a0478828fa10efb4c27a2e..72116dde77ffeb5f073dd3cc35a340333f4518f2 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2012-08-07  Jan Beulich <jbeulich@suse.com>
+
+       * config/tc-i386-intel.c (build_modrm_byte): Split determining
+       default segment from figuring out encoding. Honor RegRex for
+       the former.
+
 2012-08-07  Jan Beulich <jbeulich@suse.com>
 
        * config/tc-i386.c (set_check): Renamed from set_sse_check.

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 7cc6fa71e092d7ed39ea61c596c5ed0cfc602063..171749e08b99318c3612e6de294710b95a4e3127 100644 (file)
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -5770,18 +5770,14 @@ build_modrm_byte (void)
              i.sib.base = i.base_reg->reg_num;
              /* x86-64 ignores REX prefix bit here to avoid decoder
                 complications.  */
-             if ((i.base_reg->reg_num & 7) == EBP_REG_NUM)
-               {
+             if (!(i.base_reg->reg_flags & RegRex)
+                 && (i.base_reg->reg_num == EBP_REG_NUM
+                  || i.base_reg->reg_num == ESP_REG_NUM))
                  default_seg = &ss;
-                 if (i.disp_operands == 0)
-                   {
-                     fake_zero_displacement = 1;
-                     i.types[op].bitfield.disp8 = 1;
-                   }
-               }
-             else if (i.base_reg->reg_num == ESP_REG_NUM)
+             if (i.base_reg->reg_num == 5 && i.disp_operands == 0)
                {
-                 default_seg = &ss;
+                 fake_zero_displacement = 1;
+                 i.types[op].bitfield.disp8 = 1;
                }
              i.sib.scale = i.log2_scale_factor;
              if (i.index_reg == 0)

diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index 8225b2327b400481672ab2dd61988dd9eaf51832..56a01d8fd3f50031246f38c1a43af68c13246af3 100644 (file)
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-08-07  Jan Beulich <jbeulich@suse.com>
+
+       * gas/i386/x86-64-segovr.{s,l}: New.
+       * gas/i386/i386.exp: Run new test.
+
 2012-08-07  Jan Beulich <jbeulich@suse.com>
 
        * gas/i386/vgather-check-error.{s,l}: New.

diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index fb36423061df175f632b8b8af9bf73ea1b6e1455..82cef63ab9ccf422a3f0910540b0459247cfcd33 100644 (file)
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -315,6 +315,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
     run_dump_test "x86-64-stack-suffix"
     run_list_test "x86-64-inval" "-al"
     run_list_test "x86-64-segment" "-al"
+    run_dump_test "x86-64-segovr"
     run_list_test "x86-64-inval-seg" "-al"
     run_dump_test "x86-64-branch"
     run_dump_test "x86-64-relax-1"

diff --git a/gas/testsuite/gas/i386/x86-64-segovr.d b/gas/testsuite/gas/i386/x86-64-segovr.d
new file mode 100644 (file)
index 0000000..76f8594
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-segovr.d
@@ -0,0 +1,41 @@
+#objdump: -dw
+#name: x86-64 segment overrides
+
+.*: +file format .*
+
+Disassembly of section .text:
+
+0+ <segovr>:
+[      ]*[a-f0-9]+:    8b 00[  ]+mov[  ]+\(%rax\),%eax
+[      ]*[a-f0-9]+:    8b 01[  ]+mov[  ]+\(%rcx\),%eax
+[      ]*[a-f0-9]+:    8b 02[  ]+mov[  ]+\(%rdx\),%eax
+[      ]*[a-f0-9]+:    8b 03[  ]+mov[  ]+\(%rbx\),%eax
+[      ]*[a-f0-9]+:    3e 8b 04 24[    ]+mov[  ]+%ds:\(%rsp\),%eax
+[      ]*[a-f0-9]+:    3e 8b 45 00[    ]+mov[  ]+%ds:((0x)?0)?\(%rbp\),%eax
+[      ]*[a-f0-9]+:    8b 06[  ]+mov[  ]+\(%rsi\),%eax
+[      ]*[a-f0-9]+:    8b 07[  ]+mov[  ]+\(%rdi\),%eax
+[      ]*[a-f0-9]+:    41 8b 00[       ]+mov[  ]+\(%r8\),%eax
+[      ]*[a-f0-9]+:    41 8b 01[       ]+mov[  ]+\(%r9\),%eax
+[      ]*[a-f0-9]+:    41 8b 02[       ]+mov[  ]+\(%r10\),%eax
+[      ]*[a-f0-9]+:    41 8b 03[       ]+mov[  ]+\(%r11\),%eax
+[      ]*[a-f0-9]+:    41 8b 04 24[    ]+mov[  ]+\(%r12\),%eax
+[      ]*[a-f0-9]+:    41 8b 45 00[    ]+mov[  ]+((0x)?0)?\(%r13\),%eax
+[      ]*[a-f0-9]+:    41 8b 06[       ]+mov[  ]+\(%r14\),%eax
+[      ]*[a-f0-9]+:    41 8b 07[       ]+mov[  ]+\(%r15\),%eax
+[      ]*[a-f0-9]+:    36 8b 00[       ]+mov[  ]+%ss:\(%rax\),%eax
+[      ]*[a-f0-9]+:    36 8b 01[       ]+mov[  ]+%ss:\(%rcx\),%eax
+[      ]*[a-f0-9]+:    36 8b 02[       ]+mov[  ]+%ss:\(%rdx\),%eax
+[      ]*[a-f0-9]+:    36 8b 03[       ]+mov[  ]+%ss:\(%rbx\),%eax
+[      ]*[a-f0-9]+:    8b 04 24[       ]+mov[  ]+\(%rsp\),%eax
+[      ]*[a-f0-9]+:    8b 45 00[       ]+mov[  ]+((0x)?0)?\(%rbp\),%eax
+[      ]*[a-f0-9]+:    36 8b 06[       ]+mov[  ]+%ss:\(%rsi\),%eax
+[      ]*[a-f0-9]+:    36 8b 07[       ]+mov[  ]+%ss:\(%rdi\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 00[    ]+mov[  ]+%ss:\(%r8\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 01[    ]+mov[  ]+%ss:\(%r9\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 02[    ]+mov[  ]+%ss:\(%r10\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 03[    ]+mov[  ]+%ss:\(%r11\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 04 24[         ]+mov[  ]+%ss:\(%r12\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 45 00[         ]+mov[  ]+%ss:((0x)?0)?\(%r13\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 06[    ]+mov[  ]+%ss:\(%r14\),%eax
+[      ]*[a-f0-9]+:    36 41 8b 07[    ]+mov[  ]+%ss:\(%r15\),%eax
+#pass

diff --git a/gas/testsuite/gas/i386/x86-64-segovr.s b/gas/testsuite/gas/i386/x86-64-segovr.s
new file mode 100644 (file)
index 0000000..08c045f
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-segovr.s
@@ -0,0 +1,9 @@
+# 64bit segment overrides
+
+       .text
+segovr:
+.irp seg, ds, ss
+ .irp reg, ax, cx, dx, bx, sp, bp, si, di, 8, 9, 10, 11, 12, 13, 14, 15
+       mov     %\seg:(%r\reg), %eax
+ .endr
+.endr