This fixes flt_arith2flt() when sizeof(arith) != 4, where arith is
long. When cemcom.ansi sees an expression like d + 1 (where d is some
double), it calls flt_arith2flt() to convert 1 to floating-point. On
machines where sizeof(arith) != 4, the code did n >>= 1 when n should
not have been changed. If n was 1, then n == 0 became true. This
caused the code to convert 1 or -1 to 0.0.
My fix assumes sizeof(arith) >= 8, so I can use n >> 32. Machines
with sizeof(arith) of 5 to 7 would need to do (uarith)n >> 32, where
uarith must be an unsigned integer type of same size as arith.
In startrek.c, the Enterprise can now dock with a starbase. The
compiler no longer translates s1 - 1 to s1 - 0.0 and s1 + 1 to s1 +
0.0, so the game now looks for starbases next to the Enterprise.
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.
These files "magically reappeared" after the conversion from CVS to
Mercurial. The old CVS repository deleted these files but did not
record *when* it deleted these files. The conversion resurrected these
files because they have no history of deletion. These files were
probably deleted before year 1995. The CVS repository begins to record
deletions around 1995.
These files may still appear in older revisions of this Mercurial
repository, when they should already be deleted. There is no way to fix
this, because the CVS repository provides no dates of deletion.
See http://sourceforge.net/mailarchive/message.php?msg_id=29823032
