stepcompress: Do all step rounding in C code

Commits f0cefebf and 8f331f08 changed the way the code determined what
steps to take on fractional steps.  Unfortunately, it was possible in
some situations for the C code to round differently from the python
code which could result in warnings and lost steps.

Change the code so that all fractional step handling is done in the C
code.  Implementing the step rounding logic in one location avoids any
conflicts.

In order to efficiently handle the step rounding in the C code, the C
code has also been extended to directly send the "set_next_step_dir"
command.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 6 insertions, 4 deletions

diff --git a/klippy/chelper.py b/klippy/chelper.py
index 5b7837ee..a3ce4a95 100644
--- a/klippy/chelper.py
+++ b/klippy/chelper.py
@@ -13,12 +13,14 @@ OTHER_FILES = ['list.h', 'serialqueue.h']
 
 defs_stepcompress = """
     struct stepcompress *stepcompress_alloc(uint32_t max_error
-        , uint32_t queue_step_msgid, uint32_t oid);
-    void stepcompress_push(struct stepcompress *sc, double step_clock);
-    double stepcompress_push_factor(struct stepcompress *sc
+        , uint32_t queue_step_msgid, uint32_t set_next_step_dir_msgid
+        , uint32_t invert_sdir, uint32_t oid);
+    void stepcompress_push(struct stepcompress *sc, double step_clock
+        , int32_t sdir);
+    int32_t stepcompress_push_factor(struct stepcompress *sc
         , double steps, double step_offset
         , double clock_offset, double factor);
-    double stepcompress_push_sqrt(struct stepcompress *sc
+    int32_t stepcompress_push_sqrt(struct stepcompress *sc
         , double steps, double step_offset
         , double clock_offset, double sqrt_offset, double factor);
     void stepcompress_reset(struct stepcompress *sc, uint64_t last_step_clock);