This undoes part of bfeb736, and returns to using DBL_MAX_EXP and
DBL_MIN_EXP from float.h.
Add a dependency on math/localmath.h and other local header files so
libc is rebuilt when those headers change.
This restores the correct values of DBL_MAX, DBL_MIN_EXP, and related
constants. This fixes some range checks within libc, causing
atof("-36e90") and atof("1.44e-288") to return the correct values.
It seems that someone wanted to build flt_arith with a compiler that
had long but not unsigned long. This required extra code to
accomplish unsigned right shift, unsigned division, and unsigned
comparison using the signed operations. Now that we use uint32_t, we
can simply use the unsigned operations and remove the ucmp() function.
We have similar code in mach/proto/fp/ and in
lang/cem/libcc.ansi/stdlib/ext_comp.c where we use the unsigned
operations.
Some long variables become uint32_t, and some masks with 0xFFFFFFFF
disappear because uint32_t has only 32 bits.
Update flt_arith.3 to show that mantissa uses uint32_t.
Provide a target to install modules/src/flt_arith/test.c as flt_test
so I can run the tests.
This seems to fix an error when flt_arith converts a literal
double-precision float to IEEE format. For example, 0.5 and 0.75 got
converted to slightly below their correct values.
My host gcc for amd64 has 64-bit long, but flt_arith needs only 32
bits. The code (at least flt_add.c) can make 32-bit overflows. Such
overflows would set the higher bits of a 64-bit long, which might
cause problems later.
I need to use uint32_t and not int32_t because the code still uses
long, and the sign extension from int32_t to long would cause
problems. The mantissa represents a value in [0, 2) that can't be
negative, so unsigned type is better. Also, signed overflow is
undefined behavior in C, so flt_add.c better make overflows with
uint32_t and not int32_t.
This commit doesn't touch lang/cem/libcc.ansi/stdlib/ext_fmt.h which
continues to use unsigned long for its mantissa fields.
register 'type'; now use int/float/long/double throughout to identify
registers. Lots of register allocator tweaks and table bugfixes --- we now get
through the dreading Mathlib.mod!
