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| author | Mattias Andrée <m@maandree.se> | 2026-02-11 11:20:10 +0100 |
|---|---|---|
| committer | Mattias Andrée <m@maandree.se> | 2026-02-11 11:20:10 +0100 |
| commit | 0d4c3e8f6be098e953502589b17cb28197322442 (patch) | |
| tree | df3a13e786769e78d3d6201150f4018dc0c22cb5 /libj2_j2i_sub_j2i.3 | |
| parent | Test sat_add (diff) | |
| download | libj2-0d4c3e8f6be098e953502589b17cb28197322442.tar.gz libj2-0d4c3e8f6be098e953502589b17cb28197322442.tar.bz2 libj2-0d4c3e8f6be098e953502589b17cb28197322442.tar.xz | |
Finish signed saturated math
Signed-off-by: Mattias Andrée <m@maandree.se>
Diffstat (limited to 'libj2_j2i_sub_j2i.3')
| -rw-r--r-- | libj2_j2i_sub_j2i.3 | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/libj2_j2i_sub_j2i.3 b/libj2_j2i_sub_j2i.3 index 466c84a..c0b7a35 100644 --- a/libj2_j2i_sub_j2i.3 +++ b/libj2_j2i_sub_j2i.3 @@ -31,6 +31,15 @@ int \fBlibj2_j2i_rsub_ji_overflow\fP(struct libj2_j2i *\fIb\fP, intmax_t \fIa\fP int \fBlibj2_j2i_rsub_j2i_overflow_p\fP(const struct libj2_j2i *\fIb\fP, const struct libj2_j2i *\fIa\fP); int \fBlibj2_j2i_rsub_ji_overflow_p\fP(const struct libj2_j2i *\fIb\fP, intmax_t \fIa\fP); + +void \fBlibj2_j2i_sat_sub_j2i\fP(struct libj2_j2i *\fIa\fP, const struct libj2_j2i *\fIb\fP); +void \fBlibj2_j2i_sat_sub_j2i_to_j2i\fP(const struct libj2_j2i *\fIa\fP, const struct libj2_j2i *\fIb\fP, struct libj2_j2i *\fIr\fP); +void \fBlibj2_j2i_sat_sub_ji\fP(struct libj2_j2i *\fIa\fP, intmax_t \fIb\fP); +void \fBlibj2_j2i_sat_sub_ji_to_j2i\fP(const struct libj2_j2i *\fIa\fP, intmax_t \fIb\fP, struct libj2_j2i *\fIr\fP); +void \fBlibj2_ji_sat_sub_j2i_to_j2i\fP(intmax_t \fIa\fP, const struct libj2_j2i *\fIb\fP, struct libj2_j2i *\fIr\fP); + +void \fBlibj2_j2i_sat_rsub_j2i\fP(struct libj2_j2i *\fIb\fP, const struct libj2_j2i *\fIa\fP); +void \fBlibj2_j2i_sat_rsub_ji\fP(struct libj2_j2i *\fIb\fP, intmax_t \fIa\fP); .fi .PP Link with @@ -56,15 +65,17 @@ except the functions .BR libj2_ji_sub_j2i_overflow_p (), .BR libj2_j2i_rsub_j2i_overflow_p (), and -.BR libj2_j2i_rsub_ji_overflow_p (), +.BR libj2_j2i_rsub_ji_overflow_p () only predict overflow, and do not calculate the difference, and therefore does store it anywhere; and except the functions .BR libj2_j2i_rsub_j2i (), .BR libj2_j2i_rsub_ji (), .BR libj2_j2i_rsub_j2i_overflow (), -and .BR libj2_j2i_rsub_ji_overflow (), +.BR libj2_j2i_sat_rsub_j2i (), +and +.BR libj2_j2i_sat_rsub_ji () store the result in .IR b . .PP @@ -75,7 +86,14 @@ in their name), detect arithmetic overflow. .PP The result is truncated to the least significant bits, as many as can be stored, in case of overflow; -that is, modular arithmetics is used. +that is, modular arithmetics is used. However, the +.BR sat_sub - +and +.BR sat_rsub -functions +use saturated arithmetics, meaning that the result +will be the maximum representable value on positive +overflow and the minimum representable value on +negative overflow. .PP The arguments are assumed to be .RI non- NULL . @@ -110,8 +128,15 @@ The .BR libj2_j2i_rsub_j2i_overflow (), .BR libj2_j2i_rsub_ji_overflow (), .BR libj2_j2i_rsub_j2i_overflow_p (), +.BR libj2_j2i_rsub_ji_overflow_p (), +.BR libj2_j2i_sat_sub_j2i (), +.BR libj2_j2i_sat_sub_j2i_to_j2i (), +.BR libj2_j2i_sat_sub_ji (), +.BR libj2_j2i_sat_sub_ji_to_j2i (), +.BR libj2_ji_sat_sub_j2i_to_j2i (), +.BR libj2_j2i_sat_rsub_j2i (), and -.BR libj2_j2i_rsub_ji_overflow_p () +.BR libj2_j2i_sat_rsub_ji () functions were added in version 1.1 of .BR libj2 . |