- 02/21/08 00:57:51 (5 years ago)
- 8 added
- 1 edited
r8879 r9079 943 943 config FPE_FASTFPE 944 944 bool "FastFPE math emulation (EXPERIMENTAL)" 945 depends on (!AEABI || OABI_COMPAT) && !CPU_32v3 &&EXPERIMENTAL 945 depends on (!AEABI || OABI_COMPAT) && EXPERIMENTAL 946 946 ---help--- 947 947 Say Y here to include the FAST floating point emulator in the kernel. 948 This is an experimental much faster emulator which now also has full 949 precision for the mantissa. It does not support any exceptions. 950 It is very simple, and approximately 3-6 times faster than NWFPE. 951 952 It should be sufficient for most programs. It may be not suitable 953 for scientific calculations, but you have to check this for yourself. 954 If you do not feel you need a faster FP emulation you should better 955 choose NWFPE. 948 This is an experimental much faster emulator which is written 949 completely in ARM assembly. All instructions that are not marked as 950 deprecated in the ARM7500FE data sheet are implemented. It supports 951 single, double and double extended precision. It does support 952 exception flags, but not raising exceptions. It gives an average 953 5 times speed increase over NWFPE for FP only code. 954 955 FastFPE does not require long multiply instruction anymore and is 956 now suitable for all ARM cpus. The presence of the long multiply 957 instruction is detected during initialisation and used to speedup 958 multiply and divide. 959 960 Compliance to IEEE Std 754-1985 was verified using the testfloat 961 program of the SoftFloat package version 2a by John Hauser. All 962 operations except square root were reported to be compliant. However, 963 this is not a proof, and especially does not verify the instruction 964 parser. 965 966 You can compile both emulators into the kernel and choose one 967 of them at boot time by passing "fpe=fastfpe" or "fpe=nwfpe" as 968 kernel parameter. 969 970 It is also possible to say M to build the emulator as a module 971 (fastfpe.o). This was never tested. Only do it if you know what 972 you are doing! 973 956 974 957 975 config VFP
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