1.file "significandf.s"
2
3
4// Copyright (c) 2000 - 2003, Intel Corporation
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22
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38//
39// History
40//==============================================================
41// 02/02/00 Initial version
42// 02/03/00 Modified to improve speed
43// 05/31/00 Fixed bug when x a double-extended denormal
44// 05/20/02 Cleaned up namespace and sf0 syntax
45// 02/10/03 Reordered header: .section, .global, .proc, .align
46//
47// API
48//==============================================================
49// float significandf(float x)
50// Overview of operation
51//==============================================================
52// If x = sig * 2**n with 1 <= sig < 2
53// significandf returns sig
54//
55// predicate registers used:
56// p6, p7
57//
58// floating-point registers used:
59// f8, f9, f10
60
61.section .text
62GLOBAL_LIBM_ENTRY(significandf)
63
64// qnan snan inf norm     unorm 0 -+
65// 1    1    1   0        0     1 11
66
67// f10 gets f8(sign) with f1(exp,significand)
68{ .mfi
69      nop.m 999
70      fmerge.s       f10 = f8,f1
71      nop.i 999
72}
73{ .mfi
74      nop.m 999
75      fnorm.s0          f9  = f8
76      nop.i 999 ;;
77}
78
79// Test for denormal input
80{ .mfi
81      nop.m 999
82      fclass.m.unc   p7,p0 = f8, 0x0b
83      nop.i 999 ;;
84}
85
86// p6 = TRUE ==> x is not (nan,inf,0)
87//               return sign(f8) exp(f1) significand(f8)
88// else          x is (nan,inf,0)
89//               return sign(f8) exp(f8) significand(f8), normalized.
90{ .mfi
91      nop.m 999
92      fclass.m.unc   p0,p6 = f8, 0xe7
93      nop.i 999 ;;
94}
95
96{ .mmb
97      nop.m 999
98      nop.m 999
99(p7)  br.cond.spnt SIGNIFICAND_DENORM ;; // Branch if x denormal
100}
101
102{ .mfi
103      nop.m 999
104(p6)  fmerge.se      f8 = f10,f8
105      nop.i 999 ;;
106}
107
108{ .mfb
109      nop.m 999
110      fnorm.s.s0        f8 = f8
111      br.ret.sptk    b0 ;;
112}
113
114SIGNIFICAND_DENORM:
115// Here if x denorm
116{ .mfi
117      nop.m 999
118      fmerge.se      f8 = f10,f9
119      nop.i 999 ;;
120}
121
122// Check if fnorm(x) still denormal, means x double-extended denormal
123{ .mfi
124      nop.m 999
125      fclass.m.unc   p7,p0 = f9, 0x0b
126      nop.i 999 ;;
127}
128
129// This will be the final result unless x double-extended denormal
130{ .mfi
131      nop.m 999
132      fnorm.s.s0        f8 = f8
133      nop.i 999 ;;
134}
135
136// If x double-extended denorm, then significand ok, but must merge in
137//    correct signexp
138{ .mfi
139      nop.m 999
140(p7)  fmerge.se      f8 = f10,f8
141      nop.i 999 ;;
142}
143
144// Final normalization if x double-extended denorm
145{ .mfb
146      nop.m 999
147(p7)  fnorm.s.s0        f8 = f8
148      br.ret.sptk    b0 ;;
149}
150
151GLOBAL_LIBM_END(significandf)
152