math.c

linux-2.6.15.6

/*
 *  arch/s390/math-emu/math.c
 *
 *  S390 version
 *    Copyright (C) 1999-2001 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky ([e-mail]),
 *
 * 'math.c' emulates IEEE instructions on a S390 processor
 *          that does not have the IEEE fpu (all processors before G5).
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>

#include "sfp-util.h"
#include <math-emu/soft-fp.h>
#include <math-emu/single.h>
#include <math-emu/double.h>
#include <math-emu/quad.h>

/*
 * I miss a macro to round a floating point number to the
 * nearest integer in the same floating point format.
 */
#define _FP_TO_FPINT_ROUND(fs, wc, X)					\
  do {									\
    switch (X##_c)							\
      {									\
      case FP_CLS_NORMAL:						\
        if (X##_e > _FP_FRACBITS_##fs + _FP_EXPBIAS_##fs)		\
          { /* floating point number has no bits after the dot. */	\
          }								\
        else if (X##_e <= _FP_FRACBITS_##fs + _FP_EXPBIAS_##fs &&	\
                 X##_e > _FP_EXPBIAS_##fs)				\
	  { /* some bits before the dot, some after it. */		\
            _FP_FRAC_SRS_##wc(X, _FP_WFRACBITS_##fs,			\
                              X##_e - _FP_EXPBIAS_##fs			\
                              + _FP_FRACBITS_##fs);			\
	    _FP_ROUND(wc, X);						\
	    _FP_FRAC_SLL_##wc(X, X##_e - _FP_EXPBIAS_##fs		\
                              + _FP_FRACBITS_##fs);			\
          }								\
        else								\
          { /* all bits after the dot. */				\
	    FP_SET_EXCEPTION(FP_EX_INEXACT);				\
            X##_c = FP_CLS_ZERO;					\
	  }								\
        break;								\
      case FP_CLS_NAN:							\
      case FP_CLS_INF:							\
      case FP_CLS_ZERO:							\
        break;								\
      }									\
  } while (0)

#define FP_TO_FPINT_ROUND_S(X)	_FP_TO_FPINT_ROUND(S,1,X)
#define FP_TO_FPINT_ROUND_D(X)	_FP_TO_FPINT_ROUND(D,2,X)
#define FP_TO_FPINT_ROUND_Q(X)	_FP_TO_FPINT_ROUND(Q,4,X)

typedef union {
        long double ld;
        struct {
                __u64 high;
                __u64 low;
        } w;
} mathemu_ldcv;

#ifdef CONFIG_SYSCTL
int sysctl_ieee_emulation_warnings=1;
#endif

#define mathemu_put_user(x, p) \
        do { \
                if (put_user((x),(p))) \
                        return SIGSEGV; \
        } while (0)

#define mathemu_get_user(x, p) \
        do { \
                if (get_user((x),(p))) \
                        return SIGSEGV; \
        } while (0)

#define mathemu_copy_from_user(d, s, n)\
        do { \
                if (copy_from_user((d),(s),(n)) != 0) \
                        return SIGSEGV; \
        } while (0)

#define mathemu_copy_to_user(d, s, n) \
        do { \
                if (copy_to_user((d),(s),(n)) != 0) \
                        return SIGSEGV; \
        } while (0)

static void display_emulation_not_implemented(struct pt_regs *regs, char *instr)
{
        __u16 *location;
        
#ifdef CONFIG_SYSCTL
        if(sysctl_ieee_emulation_warnings)
#endif
        {
                location = (__u16 *)(regs->psw.addr-S390_lowcore.pgm_ilc);
                printk("%s ieee fpu instruction not emulated "
                       "process name: %s pid: %d \n",
                       instr, current->comm, current->pid);
                printk("%s's PSW:    %08lx %08lx\n", instr,
                       (unsigned long) regs->psw.mask,
                       (unsigned long) location);
        }
}

static inline void emu_set_CC (struct pt_regs *regs, int cc)
{
        regs->psw.mask = (regs->psw.mask & 0xFFFFCFFF) | ((cc&3) << 12);
}

/*
 * Set the condition code in the user psw.
 *  0 : Result is zero
 *  1 : Result is less than zero
 *  2 : Result is greater than zero
 *  3 : Result is NaN or INF
 */
static inline void emu_set_CC_cs(struct pt_regs *regs, int class, int sign)
{
        switch (class) {
        case FP_CLS_NORMAL:
        case FP_CLS_INF:
                emu_set_CC(regs, sign ? 1 : 2);
                break;
        case FP_CLS_ZERO:
                emu_set_CC(regs, 0);
                break;
        case FP_CLS_NAN:
                emu_set_CC(regs, 3);
                break;
        }
}

/* Add long double */
static int emu_axbr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_Q(QA); FP_DECL_Q(QB); FP_DECL_Q(QR);
        FP_DECL_EX;
	mathemu_ldcv cvt;
        int mode;

	mode = current->thread.fp_regs.fpc & 3;
        cvt.w.high = current->thread.fp_regs.fprs[rx].ui;
        cvt.w.low = current->thread.fp_regs.fprs[rx+2].ui;
        FP_UNPACK_QP(QA, &cvt.ld);
        cvt.w.high = current->thread.fp_regs.fprs[ry].ui;
        cvt.w.low = current->thread.fp_regs.fprs[ry+2].ui;
        FP_UNPACK_QP(QB, &cvt.ld);
        FP_ADD_Q(QR, QA, QB);
        FP_PACK_QP(&cvt.ld, QR);
        current->thread.fp_regs.fprs[rx].ui = cvt.w.high;
        current->thread.fp_regs.fprs[rx+2].ui = cvt.w.low;
        emu_set_CC_cs(regs, QR_c, QR_s);
        return _fex;
}

/* Add double */
static int emu_adbr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR);
        FP_DECL_EX;
        int mode;

	mode = current->thread.fp_regs.fpc & 3;
        FP_UNPACK_DP(DA, &current->thread.fp_regs.fprs[rx].d);
        FP_UNPACK_DP(DB, &current->thread.fp_regs.fprs[ry].d);
        FP_ADD_D(DR, DA, DB);
	FP_PACK_DP(&current->thread.fp_regs.fprs[rx].d, DR);
        emu_set_CC_cs(regs, DR_c, DR_s);
        return _fex;
}

/* Add double */
static int emu_adb (struct pt_regs *regs, int rx, double *val) {
        FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR);
        FP_DECL_EX;
        int mode;

	mode = current->thread.fp_regs.fpc & 3;
        FP_UNPACK_DP(DA, &current->thread.fp_regs.fprs[rx].d);
        FP_UNPACK_DP(DB, val);
        FP_ADD_D(DR, DA, DB);
	FP_PACK_DP(&current->thread.fp_regs.fprs[rx].d, DR);
        emu_set_CC_cs(regs, DR_c, DR_s);
        return _fex;
}

/* Add float */
static int emu_aebr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR);
        FP_DECL_EX;
        int mode;

	mode = current->thread.fp_regs.fpc & 3;
        FP_UNPACK_SP(SA, &current->thread.fp_regs.fprs[rx].f);
        FP_UNPACK_SP(SB, &current->thread.fp_regs.fprs[ry].f);
        FP_ADD_S(SR, SA, SB);
	FP_PACK_SP(&current->thread.fp_regs.fprs[rx].f, SR);
        emu_set_CC_cs(regs, SR_c, SR_s);
        return _fex;
}

/* Add float */
static int emu_aeb (struct pt_regs *regs, int rx, float *val) {
        FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR);
        FP_DECL_EX;
        int mode;

	mode = current->thread.fp_regs.fpc & 3;
        FP_UNPACK_SP(SA, &current->thread.fp_regs.fprs[rx].f);
        FP_UNPACK_SP(SB, val);
        FP_ADD_S(SR, SA, SB);
	FP_PACK_SP(&current->thread.fp_regs.fprs[rx].f, SR);
        emu_set_CC_cs(regs, SR_c, SR_s);
        return _fex;
}

/* Compare long double */
static int emu_cxbr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_Q(QA); FP_DECL_Q(QB);
	mathemu_ldcv cvt;
        int IR;

        cvt.w.high = current->thread.fp_regs.fprs[rx].ui;
        cvt.w.low = current->thread.fp_regs.fprs[rx+2].ui;
        FP_UNPACK_RAW_QP(QA, &cvt.ld);
        cvt.w.high = current->thread.fp_regs.fprs[ry].ui;
        cvt.w.low = current->thread.fp_regs.fprs[ry+2].ui;
        FP_UNPACK_RAW_QP(QB, &cvt.ld);
        FP_CMP_Q(IR, QA, QB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        return 0;
}

/* Compare double */
static int emu_cdbr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_D(DA); FP_DECL_D(DB);
        int IR;

        FP_UNPACK_RAW_DP(DA, &current->thread.fp_regs.fprs[rx].d);
        FP_UNPACK_RAW_DP(DB, &current->thread.fp_regs.fprs[ry].d);
        FP_CMP_D(IR, DA, DB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        return 0;
}

/* Compare double */
static int emu_cdb (struct pt_regs *regs, int rx, double *val) {
        FP_DECL_D(DA); FP_DECL_D(DB);
        int IR;

        FP_UNPACK_RAW_DP(DA, &current->thread.fp_regs.fprs[rx].d);
        FP_UNPACK_RAW_DP(DB, val);
        FP_CMP_D(IR, DA, DB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        return 0;
}

/* Compare float */
static int emu_cebr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_S(SA); FP_DECL_S(SB);
        int IR;

        FP_UNPACK_RAW_SP(SA, &current->thread.fp_regs.fprs[rx].f);
        FP_UNPACK_RAW_SP(SB, &current->thread.fp_regs.fprs[ry].f);
        FP_CMP_S(IR, SA, SB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        return 0;
}

/* Compare float */
static int emu_ceb (struct pt_regs *regs, int rx, float *val) {
        FP_DECL_S(SA); FP_DECL_S(SB);
        int IR;

        FP_UNPACK_RAW_SP(SA, &current->thread.fp_regs.fprs[rx].f);
        FP_UNPACK_RAW_SP(SB, val);
        FP_CMP_S(IR, SA, SB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        return 0;
}

/* Compare and signal long double */
static int emu_kxbr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_Q(QA); FP_DECL_Q(QB);
        FP_DECL_EX;
	mathemu_ldcv cvt;
        int IR;

        cvt.w.high = current->thread.fp_regs.fprs[rx].ui;
        cvt.w.low = current->thread.fp_regs.fprs[rx+2].ui;
        FP_UNPACK_RAW_QP(QA, &cvt.ld);
        cvt.w.high = current->thread.fp_regs.fprs[ry].ui;
        cvt.w.low = current->thread.fp_regs.fprs[ry+2].ui;
        FP_UNPACK_QP(QB, &cvt.ld);
        FP_CMP_Q(IR, QA, QB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        if (IR == 3)
                FP_SET_EXCEPTION (FP_EX_INVALID);
        return _fex;
}

/* Compare and signal double */
static int emu_kdbr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_D(DA); FP_DECL_D(DB);
        FP_DECL_EX;
        int IR;

        FP_UNPACK_RAW_DP(DA, &current->thread.fp_regs.fprs[rx].d);
        FP_UNPACK_RAW_DP(DB, &current->thread.fp_regs.fprs[ry].d);
        FP_CMP_D(IR, DA, DB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        if (IR == 3)
                FP_SET_EXCEPTION (FP_EX_INVALID);
        return _fex;
}

/* Compare and signal double */
static int emu_kdb (struct pt_regs *regs, int rx, double *val) {
        FP_DECL_D(DA); FP_DECL_D(DB);
        FP_DECL_EX;
        int IR;

        FP_UNPACK_RAW_DP(DA, &current->thread.fp_regs.fprs[rx].d);
        FP_UNPACK_RAW_DP(DB, val);
        FP_CMP_D(IR, DA, DB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        if (IR == 3)
                FP_SET_EXCEPTION (FP_EX_INVALID);
        return _fex;
}

/* Compare and signal float */
static int emu_kebr (struct pt_regs *regs, int rx, int ry) {
        FP_DECL_S(SA); FP_DECL_S(SB);
        FP_DECL_EX;
        int IR;

        FP_UNPACK_RAW_SP(SA, &current->thread.fp_regs.fprs[rx].f);
        FP_UNPACK_RAW_SP(SB, &current->thread.fp_regs.fprs[ry].f);
        FP_CMP_S(IR, SA, SB, 3);
        /*
         * IR == -1 if DA < DB, IR == 0 if DA == DB,
         * IR == 1 if DA > DB and IR == 3 if unorderded
         */
        emu_set_CC(regs, (IR == -1) ? 1 : (IR == 1) ? 2 : IR);
        if (IR == 3)
                FP_SET_EXCEPTION (FP_EX_INVALID);
        return _fex;
}