File sstep_motion.c¶

FileList > src > sstep_motion.c

#include "sstep_internal.h"

Public Functions¶

Type	Name
uint32_t	sstep_isqrt64 (uint64_t x) Integer square root: floor(sqrt(x)).
uint8_t	sstep_motion_step (struct sstep_motion * mo) One slow loop period of the motion generator: trapezoidal velocity profile with one-period look-ahead braking for moves, exact stop on the target.

Public Static Functions¶

Type	Name
int32_t	abs_i32 (int32_t v) \|v\|; velocities are limited to \|v\| < 2^30, so -v cannot overflow.
int64_t	abs_i64 (int64_t v) \|v\|; positions differences are far below 2^63.
int32_t	clamp_i32 (int32_t v, int32_t lo, int32_t hi) v limited to lo .
int64_t	half_floor (int64_t v) floor(v / 2) without shifting a signed value.
int32_t	target_velocity (const struct sstep_motion * mo) Velocity the profile aims at in this period.

Public Functions Documentation¶

function sstep_isqrt64¶

Integer square root: floor(sqrt(x)).

uint32_t sstep_isqrt64 (
    uint64_t x
)

Parameters:

x Value.

Returns:

floor(sqrt(x)).

function sstep_motion_step¶

One slow loop period of the motion generator: trapezoidal velocity profile with one-period look-ahead braking for moves, exact stop on the target.

uint8_t sstep_motion_step (
    struct sstep_motion * mo
)

Parameters:

mo Motion state; pos and vel are updated.

Returns:

SSTEP_MOTION_DONE when a move reached its target in this period, else 0.

Public Static Functions Documentation¶

function abs_i32¶

|v|; velocities are limited to |v| < 2^30, so -v cannot overflow.

static int32_t abs_i32 (
    int32_t v
)

function abs_i64¶

|v|; positions differences are far below 2^63.

static int64_t abs_i64 (
    int64_t v
)

function clamp_i32¶

v limited to lo .

static int32_t clamp_i32 (
    int32_t v,
    int32_t lo,
    int32_t hi
)

. hi.

function half_floor¶

floor(v / 2) without shifting a signed value.

static int64_t half_floor (
    int64_t v
)

function target_velocity¶

Velocity the profile aims at in this period.

static int32_t target_velocity (
    const struct sstep_motion * mo
)

A move aims at the largest v_new for which the distance of this period, (v + v_new) / 2, plus the braking distance from v_new, v_new^2 / (2 dec), fits into the distance left: v_new = (-dec + sqrt(dec^2 + 8 dec |rem| - 4 dec |v|)) / 2. No overshoot; the velocity changes by at most acc or dec per period, except in the last period of a move, where the remaining v <= 2 dec (a few microsteps per second) drops to zero on the target.

The documentation for this class was generated from the following file src/sstep_motion.c