1$NetBSD: README.NetBSD,v 1.2 2002/03/24 23:04:03 bjh21 Exp $ 2 3 4Changes at initial import...ross@netbsd.org 5 6 o WARNS=2 fixes 7 o source reorganized with arch/ 8 o <sys/endian.h> conversion 9 o <inttypes.h> conversion 10 o <ieeefp.h> conversion 11 o <asm.h> conversion 12 o the previously target-specific softfloat.h and milieu.h made mostly 13 generic. Still some work to do with default NaN bitpatterns, endian, 14 and arm/fpa-DEMANGLE issues. 15 o arch/i386/systfloat.S extended to handle: 16 int32_t syst_floatx80_to_int32_round_to_zero(floatx80) 17 int64_t syst_floatx80_to_int64_round_to_zero(floatx80) 18 o LONG_DOUBLE_IS_FLOATX80 was used to enable both the C module system 19 access ops and the FLOATX80 tests, all of which also required FLOATX80. 20 Besides being rundundant, this made it impossible to use the asm module 21 for i386 which the package actually comes with and also made it 22 impossible to test FLOATX80 ops without compiler support even if the 23 machine actually does them. While this is arguably OK for a regression 24 test, the two cases are obviously different. Now, the tests (which 25 don't actually require any compiler-understood extended type) are 26 always run just by defining FLOATX80. If LONG_DOUBLE_IS_FLOATX80 is 27 also defined, then the C system ops are also enabled. To switch back 28 and forth, you modify only the arch/${MACHINE_ARCH}/Makefile.inc to 29 do the cpp def and add or remove systfloat.S. For regression testing, 30 it's better in C, but for testing the test itself or verifying a 31 regression, the .S module is a better reference case. 32 33 A similar change should probably be made for LONG_DOUBLE_IS_FLOAT128, 34 but we can't test that yet. 35 36 The basic rules: 37 LONG_DOUBLE_IS_FLOAT{X80,128} 38 define if you do not have a .S file and do have compiler 39 support, or have both and want to use the compiled version 40 (but then it may be necessary to remove the .S file or add 41 an ifndef to it) 42 FLOAT{X80,128} 43 define if you have either HW or SW support and want it tested 44 45 And to confuse things further: the .S files for i386 appear to have been 46 originally created by compiling C code with -S, at least as a start. 47 48 You can see some of the price of ANSI+IEEE in these files: a simple 49 conversion from floatxx to intxx requires storing, modifying, loading, 50 and restoring the modes on each conversion in order to get a specific 51 round, thanks to the four IEEE-mandated options. A pipeline/peephole 52 pass can no doubt fix this up within one function, but not if other 53 arithmetic is done in between. 54