From: Jan Beulich <jbeulich@suse.com>
To: Binutils <binutils@sourceware.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>,
"Jiang, Haochen" <haochen.jiang@intel.com>
Subject: [PATCH v2 03/14] x86: parse special opcode modifiers for .insn
Date: Fri, 10 Mar 2023 11:20:26 +0100 [thread overview]
Message-ID: <5771df73-12d8-e880-a051-86c09d6bdb06@suse.com> (raw)
In-Reply-To: <b3625235-faf6-00ad-69c2-82583531fe43@suse.com>
So called "short form" encoding is specified by a trailing "+r", whereas
a possible extension opcode is specified by the usual "/<digit>". Take
these off the expression before handing it to get_absolute_expression().
Note that on targets where / starts a comment, --divide needs passing to
gas in order to make use of the extension opcode functionality.
---
I don't think it makes sense to further complicate things and also
consider the use of quotation inside the major opcode expression.
Ambiguities in particular with "/<digit>" can easily be resolved by
simply parenthesizing the actual expression part of the construct.
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -10742,7 +10742,7 @@ signed_cons (int size)
static void
s_insn (int dummy ATTRIBUTE_UNUSED)
{
- char mnemonic[MAX_MNEM_SIZE], *line = input_line_pointer;
+ char mnemonic[MAX_MNEM_SIZE], *line = input_line_pointer, *ptr;
char *saved_ilp = find_end_of_line (line, false), saved_char;
const char *end;
unsigned int j;
@@ -10768,6 +10768,7 @@ s_insn (int dummy ATTRIBUTE_UNUSED)
current_templates = &tt;
i.tm.mnem_off = MN__insn;
+ i.tm.extension_opcode = None;
if (startswith (line, "VEX")
&& (line[3] == '.' || is_space_char (line[3])))
@@ -10994,10 +10995,46 @@ s_insn (int dummy ATTRIBUTE_UNUSED)
goto done;
}
+ /* Before processing the opcode expression, find trailing "+r" or
+ "/<digit>" specifiers. */
+ for (ptr = line; ; ++ptr)
+ {
+ unsigned long n;
+ char *e;
+
+ ptr = strpbrk (ptr, "+/,");
+ if (ptr == NULL || *ptr == ',')
+ break;
+
+ if (*ptr == '+' && ptr[1] == 'r'
+ && (ptr[2] == ',' || (is_space_char (ptr[2]) && ptr[3] == ',')))
+ {
+ *ptr = ' ';
+ ptr[1] = ' ';
+ i.short_form = true;
+ break;
+ }
+
+ if (*ptr == '/' && ISDIGIT (ptr[1])
+ && (n = strtoul (ptr + 1, &e, 8)) < 8
+ && e == ptr + 2
+ && (ptr[2] == ',' || (is_space_char (ptr[2]) && ptr[3] == ',')))
+ {
+ *ptr = ' ';
+ ptr[1] = ' ';
+ i.tm.extension_opcode = n;
+ i.tm.opcode_modifier.modrm = 1;
+ break;
+ }
+ }
+
input_line_pointer = line;
val = get_absolute_expression ();
line = input_line_pointer;
+ if (i.short_form && (val & 7))
+ as_warn ("`+r' assumes low three opcode bits to be clear");
+
for (j = 1; j < sizeof(val); ++j)
if (!(val >> (j * 8)))
break;
next prev parent reply other threads:[~2023-03-10 10:20 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-10 10:17 [PATCH v2 00/14] x86: new .insn directive Jan Beulich
2023-03-10 10:19 ` [PATCH v2 01/14] x86: introduce " Jan Beulich
2023-03-10 10:19 ` [PATCH v2 02/14] x86: parse VEX and alike specifiers for .insn Jan Beulich
2023-03-10 10:20 ` Jan Beulich [this message]
2023-03-10 10:21 ` [PATCH v2 04/14] x86: re-work build_modrm_byte()'s register assignment Jan Beulich
2023-03-10 10:21 ` [PATCH v2 05/14] x86: VexVVVV is now merely a boolean Jan Beulich
2023-03-10 10:22 ` [PATCH v2 06/14] x86: drop "shimm" special case template expansions Jan Beulich
2023-03-10 10:22 ` [PATCH v2 07/14] x86/AT&T: restrict recognition of the "absolute branch" prefix character Jan Beulich
2023-03-10 10:23 ` [PATCH v2 08/14] x86: process instruction operands for .insn Jan Beulich
2023-03-10 10:24 ` [PATCH v2 09/14] x86: handle EVEX Disp8 " Jan Beulich
2023-03-10 10:24 ` [PATCH v2 10/14] x86: allow for multiple immediates in output_disp() Jan Beulich
2023-03-10 10:25 ` [PATCH v2 11/14] x86: handle immediate operands for .insn Jan Beulich
2023-03-10 10:26 ` [PATCH v2 12/14] x86: document .insn Jan Beulich
2023-03-10 10:26 ` [PATCH v2 13/14] x86: convert testcases to use .insn Jan Beulich
2023-04-20 8:56 ` Clément Chigot
2023-04-20 9:01 ` Jan Beulich
2023-04-20 9:09 ` Clément Chigot
2023-04-20 9:19 ` Jan Beulich
2023-04-20 9:22 ` Clément Chigot
2023-03-10 10:27 ` [PATCH RFC v2 14/14] x86: .insn example - VEX-encoded instructions of original Xeon Phi Jan Beulich
2023-03-24 9:51 ` [PATCH v2 00/14] x86: new .insn directive Jan Beulich
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