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Revert "DDA: use bitmask to track active axes [...]" 

While this was an improvement of 9 clocks on AVRs, it had more
than the opposite effect on ARMs: 25 clocks slower on the slowest
step. Apparently ARMs aren't as efficient in reading and writing
single bits.

  https://github.com/Traumflug/Teacup_Firmware/issues/189#issuecomment-262837660

Performance on AVR is back to what we had before:

  ATmega sizes               '168   '328(P)   '644(P)     '1280
  Program:  19610 bytes      137%       64%       31%       16%
     Data:   2175 bytes      213%      107%       54%       27%
   EEPROM:     32 bytes        4%        2%        2%        1%

  short-moves.gcode statistics:
  LED on occurences: 888.
  LED on time minimum: 280 clock cycles.
  LED on time maximum: 549 clock cycles.
  LED on time average: 286.273 clock cycles.

  smooth-curves.gcode statistics:
  LED on occurences: 23648.
  LED on time minimum: 272 clock cycles.
  LED on time maximum: 580 clock cycles.
  LED on time average: 307.439 clock cycles.

  triangle-odd.gcode statistics:
  LED on occurences: 1636.
  LED on time minimum: 272 clock cycles.
  LED on time maximum: 539 clock cycles.
  LED on time average: 297.732 clock cycles.
This commit is contained in:
Markus Hitter 2016-11-25 20:19:38 +01:00
parent 00a28cd502
commit 3ba52e5906
2 changed files with 4 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
dda.c
View File

@ -187,7 +187,6 @@ void dda_create(DDA *dda, const TARGET *target) {
dda->id = idcnt++;
#endif
dda->active_axes = 0;
// Handle bot axes. They're subject to kinematics considerations.
code_axes_to_stepper_axes(&startpoint, target, delta_um, steps);
for (i = X; i < E; i++) {
@ -195,8 +194,6 @@ void dda_create(DDA *dda, const TARGET *target) {
delta_steps = steps[i] - startpoint_steps.axis[i];
dda->delta[i] = (uint32_t)labs(delta_steps);
if (delta_steps)
dda->active_axes |= 1 << i;
startpoint_steps.axis[i] = steps[i];
set_direction(dda, i, delta_steps);
@ -258,9 +255,6 @@ void dda_create(DDA *dda, const TARGET *target) {
dda->e_direction = (target->axis[E] >= 0)?1:0;
}
if (dda->delta[E])
dda->active_axes |= 1 << E;
if (DEBUG_DDA && (debug_flags & DEBUG_DDA))
sersendf_P(PSTR("[%ld,%ld,%ld,%ld]"),
target->axis[X] - startpoint.axis[X], target->axis[Y] - startpoint.axis[Y],
@ -572,28 +566,28 @@ void dda_start(DDA *dda) {
void dda_step(DDA *dda) {
#if ! defined ACCELERATION_TEMPORAL
if (dda->active_axes & (1 << X)) {
if (dda->delta[X]) {
move_state.counter[X] -= dda->delta[X];
if (move_state.counter[X] < 0) {
x_step();
move_state.counter[X] += dda->total_steps;
}
}
if (dda->active_axes & (1 << Y)) {
if (dda->delta[Y]) {
move_state.counter[Y] -= dda->delta[Y];
if (move_state.counter[Y] < 0) {
y_step();
move_state.counter[Y] += dda->total_steps;
}
}
if (dda->active_axes & (1 << Z)) {
if (dda->delta[Z]) {
move_state.counter[Z] -= dda->delta[Z];
if (move_state.counter[Z] < 0) {
z_step();
move_state.counter[Z] += dda->total_steps;
}
}
if (dda->active_axes & (1 << E)) {
if (dda->delta[E]) {
move_state.counter[E] -= dda->delta[E];
if (move_state.counter[E] < 0) {
e_step();

1
dda.h
View File

@ -156,7 +156,6 @@ typedef struct {
/// word boundaries only and fill smaller variables in between with gaps,
/// so keep small variables grouped together to reduce the amount of these
/// gaps. See e.g. NXP application note AN10963, page 10f.
uint8_t active_axes; ///< Bit mask of moving axes
uint8_t fast_axis; ///< number of the fast axis
/// Endstop homing