386funit.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 96 行

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*                            Open Watcom Project
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#include "standard.h"
#include "coderep.h"
#include "indvars.h"
#include "opcodes.h"
#include "sysmacro.h"
#include "model.h"
#include "sched.h"
#include "funits.h"
#include "pattern.h"

enum {
    F_NONE      = 0x0000,
    F_ALU1      = 0x0001,
    F_ALU2      = 0x0002,
    F_FOP       = 0x0004,
};

/*
    NOTE: The 486 table is the same as the 586 for the integer units,
    and like the real machine for the floating point units. That means
    that even if someone optimizes for the 486, the integer ops should
    be OK for the 586, but we'll still get the floating/integer instruction
    intermixing that makes best use of the 486 F.P. asynchronous execution.
*/
static const FU_entry FUnits486[] = {
    /* units                    unit_stall  opnd_stall */
   {F_NONE,                     0,          0},     /* NO */
   {F_ALU1,                     1,          2},     /* ALU1 */
   {F_ALU1 | F_ALU2,            1,          2},     /* ALUX */
   {F_ALU1,                     11,         11},    /* IMUL */
   {F_ALU1,                     24,         24},    /* IDIV */
   {F_FOP,                      8,          8},     /* FOP */
   {F_FOP,                      10,         10},    /* FADD */
   {F_FOP,                      16,         16},    /* FMUL */
   {F_FOP,                      73,         73},    /* FDIV */
   {F_FOP,                      241,        241},   /* TRIG */
   {F_NONE,                     0,          0},     /* CALL */
};

static const FU_entry FUnits586[] = {
    /* units                    unit_stall  opnd_stall */
   {F_NONE,                     0,          0},     /* NO */
   {F_ALU1,                     1,          2},     /* ALU1 */
   {F_ALU1 | F_ALU2,            1,          2},     /* ALUX */
   {F_ALU1,                     11,         11},    /* IMUL */
   {F_ALU1,                     24,         24},    /* IDIV */
   {F_ALU1,                     1,          1},     /* FOP */
   {F_ALU1,                     1,          3},     /* FADD */
   {F_ALU1,                     2,          3},     /* FMUL */
   {F_FOP,                      32,         32},    /* FDIV */
   {F_ALU1,                     69,         69},    /* TRIG */
   {F_NONE,                     0,          0},     /* CALL */
};


FU_entry const *FUEntry( instruction *ins )
{
    if( _CPULevel( CPU_586 ) ) {
        return( &FUnits586[ ins->u.gen_table->func_unit ] );
    } else {
        return( &FUnits486[ ins->u.gen_table->func_unit ] );
    }
}