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| author | Bor Grošelj Simić <bor.groseljsimic@telemach.net> | 2022-01-28 02:06:17 +0100 |
|---|---|---|
| committer | Quentin Carbonneaux <quentin@c9x.me> | 2022-01-28 09:24:15 +0100 |
| commit | 74d022f975f22fda20c0d1fe09a3f6fc7680f64f (patch) | |
| tree | a8b7e9e1e822d8eee5eb694984f7d45d8a7f43f0 /doc | |
| parent | b0d27d8a019811d6a4e0c0cb7ec804ab27fcec80 (diff) | |
| download | roux-74d022f975f22fda20c0d1fe09a3f6fc7680f64f.tar.gz | |
implement unsigned -> float casts
amd64 lacks an instruction for this so it has to be implemented with signed -> float casts: - Word casting is done by zero-extending the word to a long and then doing a regular signed cast. - Long casting is done by dividing by two with correct rounding if the highest bit is set and casting that to float, then adding 1 to mantissa with integer addition
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/il.txt | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/doc/il.txt b/doc/il.txt index 48ecb23..818f0a4 100644 --- a/doc/il.txt +++ b/doc/il.txt @@ -698,7 +698,9 @@ or convert a floating point into an integer and vice versa. * `stosi` -- `I(ss)` * `dtosi` -- `I(dd)` * `swtof` -- `F(ww)` + * `uwtof` -- `F(ww)` * `sltof` -- `F(ll)` + * `ultof` -- `F(ll)` Extending the precision of a temporary is done using the `ext` family of instructions. Because QBE types do not @@ -717,9 +719,9 @@ zero. Converting between signed integers and floating points is done using `stosi` (single to signed integer), `dtosi` (double to signed integer), `swtof` (signed word to float), -and `sltof` (signed long to float). These instructions -only handle signed integers, conversion to and from -unsigned types are not yet supported. +`uwtof` (unsigned word to float), `sltof` (signed long +to float) and `ultof` (unsigned long to float). Conversion +from unsigned types is not yet supported. Because of <@ Subtyping >, there is no need to have an instruction to lower the precision of an integer temporary. @@ -990,8 +992,10 @@ instructions unless you know exactly what you are doing. * `extuh` * `extuw` * `sltof` + * `ultof` * `stosi` * `swtof` + * `uwtof` * `truncd` * <@ Cast and Copy > : |