[PATCH] x86: re-order insn template fields
Jan Beulich
jbeulich@suse.com
Wed Jul 6 13:43:32 GMT 2022
This saves quite a number of shift instructions: The "operands" field
can now be retrieved by just masking (no shift), and extracting the
"extension_opcode" field now only requires a (signed) right shift, with
no prereq left one. (Of course there may be architectures where, in a
cross build, there might be no difference at all, e.g. when there are
suitable bitfield extraction insns.)
--- a/opcodes/i386-gen.c
+++ b/opcodes/i386-gen.c
@@ -1444,8 +1444,8 @@ output_i386_opcode (FILE *table, const c
fail (_("%s:%d: %s: residual opcode (0x%0*llx) too large\n"),
filename, lineno, name, 2 * length, opcode);
- fprintf (table, " { \"%s\", 0x%0*llx%s, %s, %lu,\n",
- name, 2 * (int)length, opcode, end, extension_opcode, i);
+ fprintf (table, " { \"%s\", 0x%0*llx%s, %lu, %s,\n",
+ name, 2 * (int)length, opcode, end, i, extension_opcode);
process_i386_opcode_modifier (table, opcode_modifier, space, prefix,
operand_types, lineno);
--- a/opcodes/i386-opc.h
+++ b/opcodes/i386-opc.h
@@ -929,6 +929,12 @@ typedef struct insn_template
from all other values above. */
#define Opcode_VexW 0xf /* Operand order controlled by VEX.W. */
+ /* how many operands */
+ unsigned int operands:3;
+
+ /* spare bits */
+ unsigned int :4;
+
/* (Fake) base opcode value for pseudo prefixes. */
#define PSEUDO_PREFIX 0
@@ -952,9 +958,6 @@ typedef struct insn_template
#define Prefix_REX 8 /* {rex} */
#define Prefix_NoOptimize 9 /* {nooptimize} */
- /* how many operands */
- unsigned int operands:3;
-
/* the bits in opcode_modifier are used to generate the final opcode from
the base_opcode. These bits also are used to detect alternate forms of
the same instruction */
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