9:43 a.m.
APPROVE COMMIT
NOTE: This patch has been committed
# HG changeset patch
# User Aidan Kehoe <kehoea(a)parhasard.net>
# Date 1510393370 0
# Sat Nov 11 09:42:50 2017 +0000
# Node ID c8b7adfa23c6f68a106755cc970296763c2ed59d
# Parent 7ce0eaac52e01c1f46b35f8a36d08abcd3bbc0a6
Make % behave more consistently with varying signs, bignums
src/ChangeLog addition:
2017-11-11 Aidan Kehoe <kehoea(a)parhasard.net>
* data.c:
* data.c (rem_two_fixnum): New.
Return the result of the % operator on two EMACS_INTs. Standardise
on the sign so we don't have to put up with the quirks of the
local C implementation.
* data.c (Frem):
Document the meaning of %, cross reference to the C standard;
document that the result will have the sign of NUMBER1.
* lisp.h (EMACS_INT_ABS): New.
Make a version of abs() available appropriate for an EMACS_INT.
* doprnt.c (doprnt_1):
Use this version of abs().
tests/ChangeLog addition:
2017-11-11 Aidan Kehoe <kehoea(a)parhasard.net>
* automated/lisp-tests.el:
Check for the %-equivalence documented in the C standard for
bignums too.
diff -r 7ce0eaac52e0 -r c8b7adfa23c6 src/ChangeLog
--- a/src/ChangeLog Thu Nov 09 21:59:49 2017 +0000
+++ b/src/ChangeLog Sat Nov 11 09:42:50 2017 +0000
＠＠ -1,3 +1,18 ＠＠
+2017-11-11 Aidan Kehoe <kehoea(a)parhasard.net>
+
+ * data.c:
+ * data.c (rem_two_fixnum): New.
+ Return the result of the % operator on two EMACS_INTs. Standardise
+ on the sign so we don't have to put up with the quirks of the
+ local C implementation.
+ * data.c (Frem):
+ Document the meaning of %, cross reference to the C standard;
+ document that the result will have the sign of NUMBER1.
+ * lisp.h (EMACS_INT_ABS): New.
+ Make a version of abs() available appropriate for an EMACS_INT.
+ * doprnt.c (doprnt_1):
+ Use this version of abs().
+
2017-11-09 Aidan Kehoe <kehoea(a)parhasard.net>
* mule-ccl.c (ccl_driver):
diff -r 7ce0eaac52e0 -r c8b7adfa23c6 src/data.c
--- a/src/data.c Thu Nov 09 21:59:49 2017 +0000
+++ b/src/data.c Sat Nov 11 09:42:50 2017 +0000
＠＠ -2900,9 +2900,43 ＠＠
return make_fixnum (~ fixnum_char_or_marker_to_int (number));
}
+static Lisp_Object
+rem_two_fixnum (EMACS_INT number1, EMACS_INT number2)
+{
+ EMACS_UINT val1, val2;
+ EMACS_INT sign;
+
+ if (0 == number2)
+ {
+ Fsignal (Qarith_error, Qnil);
+ }
+
+ if (number1 < 0)
+ {
+ sign = -1;
+ val1 = -number1;
+ }
+ else
+ {
+ sign = 1;
+ val1 = number1;
+ }
+
+ val2 = EMACS_INT_ABS (number2);
+
+ return make_fixnum ((EMACS_INT)((val1 % val2) * sign));
+}
+
DEFUN ("%", Frem, 2, 2, 0, /*
-Return remainder of first arg divided by second.
-Both must be integers, characters or markers.
+Return remainder of NUMBER1 divided by NUMBER2.
+
+Both must be integers, characters or markers. This is the remainder in the C
+sense, so the following equivalence (from the C standard) holds:
+
+\(eql NUMBER1 (+ (* (/ NUMBER1 NUMBER2) NUMBER2) (% NUMBER1 NUMBER2)))
+
+In this implementation, the result will have the sign of NUMBER1, something
+not standardized in C.
*/
(number1, number2))
{
＠＠ -2914,26 +2948,34 ＠＠
if (promote_args (&number1, &number2) == FIXNUM_T)
{
- if (XREALFIXNUM (number2) == 0)
- Fsignal (Qarith_error, Qnil);
- return make_fixnum (XREALFIXNUM (number1) % XREALFIXNUM (number2));
+ return rem_two_fixnum (XREALFIXNUM (number1), XREALFIXNUM (number2));
}
else
{
if (bignum_sign (XBIGNUM_DATA (number2)) == 0)
- Fsignal (Qarith_error, Qnil);
- bignum_mod (scratch_bignum, XBIGNUM_DATA (number1),
- XBIGNUM_DATA (number2));
+ {
+ Fsignal (Qarith_error, Qnil);
+ }
+ if (bignum_sign (XBIGNUM_DATA (number1)) > -1)
+ {
+ bignum_mod (scratch_bignum, XBIGNUM_DATA (number1),
+ XBIGNUM_DATA (number2));
+ }
+ else
+ {
+ bignum_neg (scratch_bignum, XBIGNUM_DATA (number1));
+ bignum_mod (scratch_bignum2, scratch_bignum,
+ XBIGNUM_DATA (number2));
+ bignum_neg (scratch_bignum, scratch_bignum2);
+ }
+
return Fcanonicalize_number (make_bignum_bg (scratch_bignum));
}
#else /* !HAVE_BIGNUM */
EMACS_INT ival1 = fixnum_char_or_marker_to_int (number1);
EMACS_INT ival2 = fixnum_char_or_marker_to_int (number2);
- if (ival2 == 0)
- Fsignal (Qarith_error, Qnil);
-
- return make_fixnum (ival1 % ival2);
+ return rem_two_fixnum (ival1, ival2);
#endif /* HAVE_BIGNUM */
}
diff -r 7ce0eaac52e0 -r c8b7adfa23c6 src/doprnt.c
--- a/src/doprnt.c Thu Nov 09 21:59:49 2017 +0000
+++ b/src/doprnt.c Sat Nov 11 09:42:50 2017 +0000
＠＠ -926,7 +926,7 ＠＠
}
}
filllen = (max (zeros_to_add, 0) + 1 /* sign flag */
- + 2 /* number flag */ + labs (padding_to_add))
+ + 2 /* number flag */ + EMACS_INT_ABS (padding_to_add))
* MAX_ICHAR_LEN;
filling = fill_cursor = alloca_ibytes (filllen);
diff -r 7ce0eaac52e0 -r c8b7adfa23c6 src/lisp.h
--- a/src/lisp.h Thu Nov 09 21:59:49 2017 +0000
+++ b/src/lisp.h Sat Nov 11 09:42:50 2017 +0000
＠＠ -503,6 +503,15 ＠＠
#define BITS_PER_EMACS_INT (SIZEOF_EMACS_INT * BITS_PER_CHAR)
+/* Make a version of abs() available appropriate for an EMACS_INT. */
+#if SIZEOF_EMACS_INT == SIZEOF_INT
+# define EMACS_INT_ABS abs
+#elif SIZEOF_EMACS_INT == SIZEOF_LONG
+# define EMACS_INT_ABS labs
+#elif SIZEOF_EMACS_INT == SIZEOF_LONG_LONG
+# define EMACS_INT_ABS llabs
+#endif
+
/* -------------------------- basic byte typedefs --------------------- */
/* The definitions we put here and in the next section use typedefs to
diff -r 7ce0eaac52e0 -r c8b7adfa23c6 tests/ChangeLog
--- a/tests/ChangeLog Thu Nov 09 21:59:49 2017 +0000
+++ b/tests/ChangeLog Sat Nov 11 09:42:50 2017 +0000
＠＠ -1,3 +1,9 ＠＠
+2017-11-11 Aidan Kehoe <kehoea(a)parhasard.net>
+
+ * automated/lisp-tests.el:
+ Check for the %-equivalence documented in the C standard for
+ bignums too.
+
2017-11-07 Aidan Kehoe <kehoea(a)parhasard.net>
* automated/mule-tests.el:
diff -r 7ce0eaac52e0 -r c8b7adfa23c6 tests/automated/lisp-tests.el
--- a/tests/automated/lisp-tests.el Thu Nov 09 21:59:49 2017 +0000
+++ b/tests/automated/lisp-tests.el Sat Nov 11 09:42:50 2017 +0000
＠＠ -757,7 +757,22 ＠＠
(= (% big (1+ most-positive-fixnum)) most-positive-fixnum)
(= (% negbig (1- most-negative-fixnum)) most-negative-fixnum)
(= (mod big (1+ most-positive-fixnum)) most-positive-fixnum)
- (= (mod negbig (1- most-negative-fixnum)) most-negative-fixnum)))
+ (= (mod negbig (1- most-negative-fixnum)) most-negative-fixnum))
+
+ (macrolet
+ ((check-%-for-value (value denominator)
+ `(Assert (eql ,value
+ (+ (* (/ ,value ,denominator) ,denominator)
+ (% ,value ,denominator))))))
+ (let ((limit (* most-positive-fixnum 2)) random-value random-denominator)
+ (dotimes (i 10) ;; Increase these COUNTs to reassure.
+ (dotimes (j 4)
+ (setq random-value (random limit)
+ random-denominator (random limit))
+ (check-%-for-value random-value random-denominator)
+ (check-%-for-value (- random-value) random-denominator)
+ (check-%-for-value random-value (- random-denominator))
+ (check-%-for-value (- random-value) (- random-denominator)))))))
;;-----------------------------------------------------
;; Arithmetic comparison operations
--
‘As I sat looking up at the Guinness ad, I could never figure out /
How your man stayed up on the surfboard after forty pints of stout’
(C. Moore)