arm/nwfpe/netwinder-fpe.rst

5 The following describes the current state of the NetWinder's floating point
8 In the following nomenclature is used to describe the floating point
14   {P|M|Z} = {round to +infinity,round to -infinity,round to zero},
15             default = round to nearest
19 Floating Point Coprocessor Data Transfer Instructions (CPDT)
20 ------------------------------------------------------------
22 LDF/STF - load and store floating
30 LFM/SFM - load and store multiple floating
41 for each floating point register into the memory location given in the
42 instruction.  The format in memory is unlikely to be compatible with
46 Floating Point Coprocessor Register Transfer Instructions (CPRT)
47 ----------------------------------------------------------------
51 FLT{cond}<S,D,E>{P,M,Z} Fn, Rd          Convert integer to floating point
52 FIX{cond}{P,M,Z} Rd, Fn                 Convert floating point to integer
53 WFS{cond} Rd                            Write floating point status register
54 RFS{cond} Rd                            Read floating point status register
55 WFC{cond} Rd                            Write floating point control register
56 RFC{cond} Rd                            Read floating point control register
75 Floating Point Coprocessor Data Instructions (CPDT)
76 ---------------------------------------------------
80 ADF{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - add
81 SUF{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - subtract
82 RSF{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - reverse subtract
83 MUF{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - multiply
84 DVF{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - divide
85 RDV{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - reverse divide
89 FML{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - fast multiply
90 FDV{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - fast divide
91 FRD{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - fast reverse divide
94 non-fast versions.  Hence, in this implementation their performance is
95 equivalent to the MUF/DVF/RDV instructions.  This is acceptable according
96 to the ARM manual.  The manual notes these are defined only for single
101 RMF{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - IEEE remainder
107 MVF{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - move
108 MNF{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - move negated
112 ABS{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - absolute value
113 SQT{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - square root
114 RND{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - round
118 URD{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - unnormalized round
119 NRM{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - normalize
127 POW{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - power
128 RPW{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - reverse power
129 POL{cond}<S|D|E>{P,M,Z} Fd, Fn, <Fm,#value> - polar angle (arctan2)
131 LOG{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - logarithm to base 10
132 LGN{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - logarithm to base e
133 EXP{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - exponent
134 SIN{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - sine
135 COS{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - cosine
136 TAN{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - tangent
137 ASN{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - arcsine
138 ACS{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - arccosine
139 ATN{cond}<S|D|E>{P,M,Z} Fd, <Fm,#value> - arctangent
143 hardware, but are handled by the floating point support code.  They should
150 is caused by a failure to alias fp_current to the kernel variable
153 The kernel provided with this distribution (vmlinux-nwfpe-0.93) contains
155 emulator directly.  It is possible to run with no floating point module
157 technology and for those who want to do floating point work that depends
158 on signals.  It is not strictly necessary to use the module.
161 distribution) can be loaded to replace the functionality of the emulator