about summary refs log tree commit diff
path: root/sysdeps/ia64/fpu/s_ilogb.S
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/ia64/fpu/s_ilogb.S')
-rw-r--r--sysdeps/ia64/fpu/s_ilogb.S306
1 files changed, 160 insertions, 146 deletions
diff --git a/sysdeps/ia64/fpu/s_ilogb.S b/sysdeps/ia64/fpu/s_ilogb.S
index 61975dd941..3f2733cabd 100644
--- a/sysdeps/ia64/fpu/s_ilogb.S
+++ b/sysdeps/ia64/fpu/s_ilogb.S
@@ -1,10 +1,10 @@
 .file "ilogb.s"
 
-// Copyright (C) 2000, 2001, Intel Corporation
+
+// Copyright (c) 2000 - 2003, Intel Corporation
 // All rights reserved.
-// 
-// Contributed 2/2/2000 by John Harrison, Ted Kubaska, Bob Norin, Shane Story,
-// and Ping Tak Peter Tang of the Computational Software Lab, Intel Corporation.
+//
+// Contributed 2000 by the Intel Numerics Group, Intel Corporation
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -20,234 +20,248 @@
 // * The name of Intel Corporation may not be used to endorse or promote
 // products derived from this software without specific prior written
 // permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS 
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS
 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
-// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 // OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
-// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
-// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
-// 
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
 // Intel Corporation is the author of this code, and requests that all
-// problem reports or change requests be submitted to it directly at 
-// http://developer.intel.com/opensource.
+// problem reports or change requests be submitted to it directly at
+// http://www.intel.com/software/products/opensource/libraries/num.htm.
 //
 // History
 //==============================================================
-// 2/03/00  Initial version
-// 5/26/00  Fix bug when x a double-extended denormal; 
+// 02/03/00 Initial version
+// 05/26/00 Fix bug when x a double-extended denormal;
 //          if x=0 call error routine, per C9X
-// 8/15/00  Bundle added after call to __libm_error_support to properly
+// 08/15/00 Bundle added after call to __libm_error_support to properly
 //          set [the previously overwritten] GR_Parameter_RESULT.
-// 1/20/01  Fixed result for x=0, corrected error tag value.
-
-.align 32
-.global ilogb#
-
-.section .text
-.proc  ilogb#
-.align 32
-
+// 01/20/01 Fixed result for x=0, corrected error tag value.
+// 05/20/02 Cleaned up namespace and sf0 syntax
+// 01/20/03 Improved performance
+//
 // API
 //==============================================================
-// int = ilogb(double)
-
+// int ilogb( double x );
+//
 // Overview of operation
 //==============================================================
-// ilogb computes log2(x) as an int
+// The ilogb function extracts the exponent of x as an integer
 // and returns it in r8
-
-// ilogb is similar to logb but differs in the  following ways:
+//
+// ilogb is similar to logb but differs in the following ways:
 //         +-inf
 //            ilogb: returns INT_MAX
 //             logb: returns +inf
-//         Nan  returns FP_ILOGBNAN (which is either INT_MAX or INT_MIN)
+//         Nan  returns FP_LOGBNAN (which is either INT_MAX or INT_MIN)
 //            ilogb: returns INT_MAX (7fffffff)
-//             logb: returns QNAN (quieted SNAN)
+//             logb: returns QNAN (quietized SNAN)
 //         0    returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
-//            ilogb: returns INT_MIN (80000000)
-//             logb: returns -inf
-
+//            ilogb: returns -INT_MAX (80000001)
+//             logb: returns -inf, raises the divide-by-zero exception,
+//                   and calls libm_error_support to set domain error
+//
 // Registers used
 //==============================================================
+// general registers used:
+// r26 -> r39
+// r36 -> r39 used as parameters to error path
+//
+// predicate registers used:
+// p6 -> p10
+// floating-point registers used:
+// f9, f10, f11
+// f8, input
 
-// general local registers: 
-// ar.pfs r32
-// r33 -> r37
-// r38 -> r41 used as parameters to error path
-
-// predicate registers used: 
-// p6 - x nan, inf
-// p7 - x 0
-// p8 - x norm, unorm
-// p9 - x unorm
-
-// floating-point registers used: 
-// f8 - f10
-
-#include "libm_support.h"
+rExpBias            = r26
+rExpMask            = r27
+rSignexp_x          = r28
+rExp_x              = r29
+rIntMax             = r30
+rExp_2to64          = r31
 
 GR_SAVE_PFS         = r32
+rTrialResult        = r33
 GR_SAVE_B0          = r34
 GR_SAVE_GP          = r35
-GR_Parameter_X      = r38
-GR_Parameter_Y      = r39
-GR_Parameter_RESULT = r40
-GR_Parameter_TAG    = r41
 
-FR_X                = f8
-FR_Y                = f0
-FR_RESULT           = f0
+GR_Parameter_X      = r36
+GR_Parameter_Y      = r37
+GR_Parameter_RESULT = r38
+GR_Parameter_TAG    = r39
 
+fTmp                = f9
+fNorm_x             = f10
+f2to64              = f11
 
-ilogb: 
+.section .text
+GLOBAL_LIBM_ENTRY(ilogb)
 
-// Form signexp of 2^64 in case need to scale denormal
-{ .mmf
-      alloc          r32=ar.pfs,1,5,4,0
-(p0)  mov      r37 = 0x1003f
-(p0)  fnorm    f9 = f8 ;;
+// X NORMAL
+// TrueExp_x = exp(f8) - 0xffff
+// r8 = TrueExp_x
+{ .mfi
+      getf.exp        rSignexp_x = f8
+      fclass.m        p8,p0 = f8, 0x0b   // Test for x unorm
+      mov             rExpBias = 0xffff  // Exponent bias
 }
-
-// Form 2^64 in case need to scale denormal
 { .mfi
-(p0)  setf.exp f10 = r37
-(p0)  fclass.m.unc p7, p8 = f8, 0xe3        
-(p0)  mov      r34 = 0xffff ;;
+      nop.m           0
+      fnorm.s1        fNorm_x = f8
+      mov             rExpMask = 0x1ffff // Exponent mask
 }
+;;
 
-// qnan snan inf norm     unorm 0 -+
-// 1    1    1   0        0     0 11
-// e                      3
-// X ZERO, returns INT_MIN
-// X INF or NAN, returns INT_MAX
+// Form signexp of 2^64 in case need to scale denormal
+{ .mfb
+      mov             rExp_2to64 = 0x1003f
+      fclass.m        p6,p9 = f8, 0x1e3  // Test x natval, nan, inf
+(p8)  br.cond.spnt    ILOGB_DENORM       // Branch if x unorm
+}
+;;
 
+ILOGB_COMMON:
+// Return here from ILOGB_DENORM
 { .mfi
-(p0)  mov      r35 = 0x1ffff
-(p8)    fclass.m.unc p6, p8 = f8, 0x07
-	nop.i 999 ;;
+      and             rExp_x = rSignexp_x, rExpMask // Get biased exponent
+      fclass.m        p7,p10 = f8, 0x07   // Test x zero
+      nop.i           0
 }
 { .mlx
-	nop.m 999
-(p7)    movl r8 = 0x000000007fffffff ;;       
+      nop.m           0
+      movl            rIntMax = 0x000000007fffffff // Form INT_MAX
 }
+;;
 
-{ .mib
-	nop.m 999
-	nop.i 999
-(p6)    br.cond.spnt  L(ILOGB_ZERO) ;;
-}
-
-// Test for denormal
+.pred.rel "mutex",p6,p9
 { .mfi
-	nop.m 999
-(p8)    fclass.m.unc p9, p0 = f9, 0x0b        
-	nop.i 999 ;;
+(p9)  sub             r8 = rExp_x, rExpBias // Get true exponent for normal path
+(p6)  fma.s0          fTmp = f8, f8, f0     // Dummy to set Invalid flag
+(p6)  mov             r8 = rIntMax          // If nan, inf, return INT_MAX
+}
+{ .mbb
+      nop.m           0
+(p7)  br.cond.spnt    ILOGB_ZERO            // Branch if x zero
+(p10) br.ret.sptk     b0                    // Exit if x not zero
 }
+;;
 
-L(ILOGB_COMMON):
-// X NORMAL returns true exponent
-{ .mmi
-	nop.m 999 
-(p8)    getf.exp r33 = f9
-	nop.i 999 ;;
+
+ILOGB_DENORM:
+// Form 2^64 in case need to scale denormal
+// Check to see if double-extended denormal
+{ .mfi
+      setf.exp        f2to64 = rExp_2to64
+      fclass.m        p8,p0 = fNorm_x, 0x0b
+      nop.i           0
 }
+;;
 
-// If denormal add 64 to exponent bias for scaling
-{ .mfb
-(p9)    add     r34 = 64, r34   
-	nop.f 999 
-(p9)    br.cond.spnt  L(ILOGB_DENORM) ;;
+{ .mfi
+      nop.m           0
+      fcmp.eq.s0      p7,p0 = f8, f0           // Dummy op to set denormal flag
+      nop.i           0
 }
+;;
 
-{ .mmi
-(p8)    and      r36 = r35, r33
-	nop.m 999
-	nop.i 999 ;;
+// If double-extended denormal add 64 to exponent bias for scaling
+// If double-extended denormal form x * 2^64 which is normal
+{ .mfi
+(p8)  add             rExpBias = 64, rExpBias
+(p8)  fmpy.s1         fNorm_x = fNorm_x, f2to64
+      nop.i           0
 }
+;;
 
+// Logic is the same as normal path but use normalized input
 { .mib
-(p8)    sub r8 = r36, r34                  
-	nop.i 999
-(p0)    br.ret.sptk    b0 ;;                     
+      getf.exp        rSignexp_x = fNorm_x
+      nop.i           0
+      br.cond.sptk    ILOGB_COMMON             // Return to main path
 }
+;;
 
-L(ILOGB_DENORM):
-// Here if x denormal
-// Form x * 2^64 which is normal
-// Return to common code
-{ .mfb
-        cmp.eq p8,p9 = r0,r0
-        fmpy f9 = f9, f10
-        br.cond.sptk  L(ILOGB_COMMON) ;;
+ILOGB_ZERO:
+// Here if x zero
+// Return INT_MIN, call error support
+
+{ .mlx
+      alloc           r32=ar.pfs,1,3,4,0
+      movl            rTrialResult = 0x0000000080000000
+}
+{ .mib
+      mov             GR_Parameter_TAG = 157  // Error code
+      nop.i           0
+      br.cond.sptk    __libm_error_region     // Call error support
 }
+;;
 
-// X ZERO
-// return INT_MIN, call error support
-L(ILOGB_ZERO): 
-{.mlx
-      mov            GR_Parameter_TAG = 157
-(p6)  movl r33 = 0x0000000080000000 ;;
-};;
-.endp ilogb
-ASM_SIZE_DIRECTIVE(ilogb)
+GLOBAL_LIBM_END(ilogb)
 
-.proc __libm_error_region
-__libm_error_region:
+LOCAL_LIBM_ENTRY(__libm_error_region)
 .prologue
+
 { .mfi
-        add   GR_Parameter_Y=-32,sp             // Parameter 2 value
+        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
+        mov  GR_SAVE_PFS=ar.pfs               // Save ar.pfs
 }
 { .mfi
 .fframe 64
-        add sp=-64,sp                           // Create new stack
+        add sp=-64,sp                         // Create new stack
         nop.f 0
-        mov GR_SAVE_GP=gp                       // Save gp
+        mov GR_SAVE_GP=gp                     // Save gp
 };;
+
 { .mmi
-        stfd [GR_Parameter_Y] = FR_Y,16         // Save Parameter 2 on stack
-        add GR_Parameter_X = 16,sp              // Parameter 1 address
+        stfd [GR_Parameter_Y] = f0,16         // 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
+        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
-        nop.b 0                                 // Parameter 3 address
+        stfd [GR_Parameter_X] = f8            // 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
+        stfd [GR_Parameter_Y] = f9            // Store Parameter 3 on stack
         add   GR_Parameter_Y = -16,GR_Parameter_Y
-        br.call.sptk b0=__libm_error_support#  // Call error handling function
+        br.call.sptk b0=__libm_error_support# // Call error handling function
 };;
+
 { .mmi
-        nop.m 0
-        nop.m 0
         add   GR_Parameter_RESULT = 48,sp
+        nop.m 0
+        nop.i 0
 };;
+
 { .mmi
-        mov   r8 = r33                         // Store result
+        mov   r8 = rTrialResult
 .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
+        br.ret.sptk   b0
 };;
 
-.endp __libm_error_region
-ASM_SIZE_DIRECTIVE(__libm_error_region)
+LOCAL_LIBM_END(__libm_error_region)
+
 
 .type   __libm_error_support#,@function
 .global __libm_error_support#