e_exp10.s

glibc 2.9,最新版的C语言库函数

}
;;

{.mfi
       ldfe FR_COEFF2= [ GR_COEFF_START ], 16    // load C_2
       fma.s1 FR_LOG2_10= f8, FR_L2_10_high, f0  // y0= x*log2(10)_hi
       mov GR_MASK_low= 31
}
;;

{.mlx
       getf.sig GR_KF0= FR_KF0                   // (K+f)*2^10= round_to_int(y)
 (p8)  movl GR_exact_limit= 0x41b00000           // Largest x for exact result,
                                                 //  +22.0
}
;;

{.mfi
       add GR_LOG_TBL= 256, GR_COEFF_START       // Pointer to high T_table
       fcmp.gt.s1 p12, p7= f8, FR_OF_LIMIT       // x>overflow threshold ?
       nop.i 0
}
;;

{.mfi
 (p8)  setf.s FR_exact_limit = GR_exact_limit    // Largest x for exact result
 (p8)  fcvt.xf FR_int_x = FR_int_x               // Integral part of x
       shr GR_K= GR_KF0, 10                      // K
}
{.mfi
       and GR_F_high= GR_MASK, GR_KF0            // f_high*32
       fnma.s1 FR_R= FR_KF, FR_2P53, FR_LOG2_10  // r= x*log2(10)-2^{63-10}*
                                                 //    [ (K+f)*2^{10-63} ]
       and GR_F_low= GR_KF0, GR_MASK_low         // f_low
}
;;

{.mmi
       shladd GR_Flow_ADDR= GR_F_low, 3, GR_COEFF_START // address of 2^{f_low}
       add GR_BIAS= GR_K, GR_EXP_CORR            // K= bias-2*63
       shr GR_Fh= GR_F_high, 5                   // f_high
}
;;

{.mfi
       setf.exp FR_2_TO_K= GR_BIAS               // 2^{K-126}
 (p7)  fcmp.lt.s1 p12, p7= f8, FR_UF_LIMIT       // x<underflow threshold ?
       shladd GR_Fh_ADDR= GR_Fh, 3, GR_LOG_TBL   // address of 2^{f_high}
}
{.mfi
       ldf8 FR_T_low= [ GR_Flow_ADDR ]           // load T_low= 2^{f_low}
       fms.s1 FR_DX_L210= f8, FR_L2_10_high, FR_LOG2_10 // x*log2(10)_hi-
                                                 //        RN(x*log2(10)_hi)
       nop.i 0
}
;;

{.mfi
       ldf8 FR_T_high= [ GR_Fh_ADDR ]            // load T_high= 2^{f_high}
       fma.s1 FR_P34= FR_COEFF4, FR_R, FR_COEFF3 // P34= C_3+C_4*r
       nop.i 0
}
{.mfb
       nop.m 0
       fma.s1 FR_R2= FR_R, FR_R, f0              // r*r
 (p12) br.cond.spnt OUT_RANGE_exp10
}
;;

{.mfi
       nop.m 0
       // e= (x*log2(10)_hi-RN(x*log2(10)_hi))+log2(10)_lo*x
       fma.s1 FR_E0= f8, FR_L2_10_low, FR_DX_L210
       cmp.eq p7,p9= r0,r0                       // Assume inexact result
}
{.mfi
       nop.m 0
       fma.s1 FR_P12= FR_COEFF2, FR_R, FR_COEFF1 // P12= C_1+C_2*r
       nop.i 0
}
;;

{.mfi
       nop.m 0
 (p8)  fcmp.eq.s1 p9,p7= FR_int_x, f8            // Test x positive integer
       nop.i 0
}
{.mfi
       nop.m 0
       fma.s1 FR_T_low_K= FR_T_low, FR_2_TO_K, f0 // T= 2^{K-126}*T_low
       nop.i 0
}
;;

{.mfi
       nop.m 0
       fcmp.ge.s1 p11,p0= f8, FR_SNORM_LIMIT      // Test x for normal range
       nop.i 0
}
;;

{.mfi
       nop.m 0
       fma.s1 FR_E= FR_E0, FR_COEFF1, f0          // E= C_1*e
       nop.i 0
}
{.mfi
       nop.m 0
       fma.s1 FR_P14= FR_R2, FR_P34, FR_P12       // P14= P12+r2*P34
       nop.i 0
}
;;

// If x a positive integer, will it produce an exact result?
//   p7 result will be inexact
//   p9 result will be exact
{.mfi
       nop.m 0
 (p9)  fcmp.le.s1 p9,p7= f8, FR_exact_limit       // Test x gives exact result
       nop.i 0
}
{.mfi
       nop.m 0
       fma.s1 FR_T= FR_T_low_K, FR_T_high, f0     // T= T*T_high
       nop.i 0
}
;;

{.mfi
       nop.m 0
       fma.s1 FR_P= FR_P14, FR_R, FR_E            // P= P14*r+E
       nop.i 0
}
;;

.pred.rel "mutex",p7,p9
{.mfi
       nop.m 0
 (p7)  fma.d.s0 f8= FR_P, FR_T, FR_T              // result= T+T*P, inexact set
       nop.i 0
}
{.mfb
       nop.m 0
 (p9)  fma.d.s1 f8= FR_P, FR_T, FR_T              // result= T+T*P, exact use s1
 (p11) br.ret.sptk b0                             // return, if result normal
}
;;

// Here if result in denormal range (and not zero)
{.mib
       nop.m 0
       mov GR_Parameter_TAG= 265
       br.cond.sptk __libm_error_region           // Branch to error handling
}
;;

SPECIAL_exp10:
{.mfi
       nop.m 0
       fclass.m p6, p0= f8, 0x22                  // x= -Infinity ?
       nop.i 0
}
;;

{.mfi
       nop.m 0
       fclass.m p7, p0= f8, 0x21                  // x= +Infinity ?
       nop.i 0
}
;;

{.mfi
       nop.m 0
       fclass.m p8, p0= f8, 0x7                   // x= +/-Zero ?
       nop.i 0
}
{.mfb
       nop.m 0
 (p6)  mov f8= f0                                 // exp10(-Infinity)= 0
 (p6)  br.ret.spnt b0
}
;;

{.mfb
       nop.m 0
       nop.f 0
 (p7)  br.ret.spnt b0                             // exp10(+Infinity)= +Infinity
}
;;

{.mfb
       nop.m 0
 (p8)  mov f8= f1                                 // exp10(+/-0)= 1
 (p8)  br.ret.spnt b0
}
;;

{.mfb
       nop.m 0
       fma.d.s0 f8= f8, f1, f0                    // Remaining cases: NaNs
       br.ret.sptk b0
}
;;


OUT_RANGE_exp10:

// underflow: p6= 1
// overflow: p8= 1

.pred.rel "mutex",p6,p8
{.mmi
 (p8)  mov GR_EXPMAX= 0x1fffe
 (p6)  mov GR_EXPMAX= 1
       nop.i 0
}
;;

{.mii
       setf.exp FR_R= GR_EXPMAX
 (p8)  mov GR_Parameter_TAG= 166
 (p6)  mov GR_Parameter_TAG= 265
}
;;

{.mfb
       nop.m 0
       fma.d.s0 f8= FR_R, FR_R, f0                // Create overflow/underflow
       br.cond.sptk __libm_error_region           // Branch to error handling
}
;;

GLOBAL_IEEE754_END(exp10)
weak_alias (exp10, pow10)


LOCAL_LIBM_ENTRY(__libm_error_region)

.prologue
{.mfi
       add GR_Parameter_Y= -32, sp                // Parameter 2 value
       nop.f 0
.save ar.pfs, GR_SAVE_PFS
       mov GR_SAVE_PFS= ar.pfs                    // Save ar.pfs
}

{.mfi
.fframe 64
       add sp= -64, sp                            // Create new stack
       nop.f 0
       mov GR_SAVE_GP= gp                         // Save gp
}
;;

{.mmi
       stfd [ GR_Parameter_Y ]= FR_Y, 16          // STORE Parameter 2 on stack
       add GR_Parameter_X= 16, sp                 // Parameter 1 address
.save b0, GR_SAVE_B0
       mov GR_SAVE_B0= b0                         // Save b0
}
;;

.body
{.mib
       stfd [ GR_Parameter_X ]= FR_X              // STORE Parameter 1 on stack
       add GR_Parameter_RESULT= 0, GR_Parameter_Y // Parameter 3 address
       nop.b 0
}
{.mib
       stfd [ GR_Parameter_Y ]= FR_RESULT         // STORE Parameter 3 on stack
       add GR_Parameter_Y= -16, GR_Parameter_Y
       br.call.sptk b0= __libm_error_support#    // Call error handling function
}
;;

{.mmi
       add GR_Parameter_RESULT= 48, sp
       nop.m 0
       nop.i 0
}
;;

{.mmi
       ldfd f8= [ GR_Parameter_RESULT ]          // Get return result off stack
.restore sp
       add sp= 64, sp                            // Restore stack pointer
       mov b0= GR_SAVE_B0                        // Restore return address
}
;;

{.mib
       mov gp= GR_SAVE_GP                        // Restore gp
       mov ar.pfs= GR_SAVE_PFS                   // Restore ar.pfs
       br.ret.sptk b0                            // Return
}
;;


LOCAL_LIBM_END(__libm_error_region)

.type __libm_error_support#, @function
.global __libm_error_support#