<p>laforge <strong>submitted</strong> this change.</p><p><a href="https://gerrit.osmocom.org/c/libosmo-abis/+/19500">View Change</a></p><div style="white-space:pre-wrap">Approvals:
Jenkins Builder: Verified
laforge: Looks good to me, approved
</div><pre style="font-family: monospace,monospace; white-space: pre-wrap;">dahdi: Use osmo_revbytebits_buf() instead of local flip table<br><br>We've had osmo_revbytebits_buf() in libosmocore for ages. As it<br>recently turned out, the flip_bits[] lookup table approach implemented<br>here is faster at least on x86 systems of the last decade or so.<br><br>As of Change-Id I25029fe7e54c92979fb0119992fb8dc167e1536e in<br>libosmocore, it has been migrated to the lookup table approach. This<br>means there's no performance penalty of migrating to using it, and<br>hence no reason whatsoever to have a private implementation here.<br><br>Change-Id: I285a87a9fc6abae7d8b47923a46cd082f46829f8<br>---<br>M src/input/dahdi.c<br>1 file changed, 8 insertions(+), 41 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/src/input/dahdi.c b/src/input/dahdi.c</span><br><span>index 0cbf9da..bf6da3e 100644</span><br><span>--- a/src/input/dahdi.c</span><br><span>+++ b/src/input/dahdi.c</span><br><span>@@ -329,33 +329,6 @@</span><br><span> </span><br><span> static int invertbits = 1;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-static uint8_t flip_table[256];</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span style="color: hsl(0, 100%, 40%);">-static void init_flip_bits(void)</span><br><span style="color: hsl(0, 100%, 40%);">-{</span><br><span style="color: hsl(0, 100%, 40%);">- int i,k;</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span style="color: hsl(0, 100%, 40%);">- for (i = 0 ; i < 256 ; i++) {</span><br><span style="color: hsl(0, 100%, 40%);">- uint8_t sample = 0 ;</span><br><span style="color: hsl(0, 100%, 40%);">- for (k = 0; k<8; k++) {</span><br><span style="color: hsl(0, 100%, 40%);">- if ( i & 1 << k ) sample |= 0x80 >> k;</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(0, 100%, 40%);">- flip_table[i] = sample;</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(0, 100%, 40%);">-}</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span style="color: hsl(0, 100%, 40%);">-static uint8_t * flip_buf_bits ( uint8_t * buf , int len)</span><br><span style="color: hsl(0, 100%, 40%);">-{</span><br><span style="color: hsl(0, 100%, 40%);">- int i;</span><br><span style="color: hsl(0, 100%, 40%);">- uint8_t * start = buf;</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span style="color: hsl(0, 100%, 40%);">- for (i = 0 ; i < len; i++) {</span><br><span style="color: hsl(0, 100%, 40%);">- buf[i] = flip_table[(uint8_t)buf[i]];</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span style="color: hsl(0, 100%, 40%);">- return start;</span><br><span style="color: hsl(0, 100%, 40%);">-}</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span> /* write to a B channel TS */</span><br><span> static int handle_tsX_write(struct osmo_fd *bfd)</span><br><span> {</span><br><span>@@ -376,9 +349,8 @@</span><br><span> </span><br><span> LOGPITS(e1i_ts, DLMIB, LOGL_DEBUG, "BCHAN TX: %s\n", osmo_hexdump(tx_buf, D_BCHAN_TX_GRAN));</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- if (invertbits) {</span><br><span style="color: hsl(0, 100%, 40%);">- flip_buf_bits(tx_buf, ret);</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(120, 100%, 40%);">+ if (invertbits)</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_revbytebits_buf(tx_buf, ret);</span><br><span> </span><br><span> ret = write(bfd->fd, tx_buf, ret);</span><br><span> if (ret < D_BCHAN_TX_GRAN)</span><br><span>@@ -407,9 +379,8 @@</span><br><span> return ret;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- if (invertbits) {</span><br><span style="color: hsl(0, 100%, 40%);">- flip_buf_bits(msg->data, ret);</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(120, 100%, 40%);">+ if (invertbits)</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_revbytebits_buf(msg->data, ret);</span><br><span> </span><br><span> msgb_put(msg, ret);</span><br><span> </span><br><span>@@ -447,9 +418,8 @@</span><br><span> </span><br><span> LOGPITS(e1i_ts, DLMIB, LOGL_DEBUG, "RAW CHAN TX: %s\n", osmo_hexdump(msg->data, msg->len));</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- if (0/*invertbits*/) {</span><br><span style="color: hsl(0, 100%, 40%);">- flip_buf_bits(msg->data, msg->len);</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(120, 100%, 40%);">+ if (0/*invertbits*/)</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_revbytebits_buf(msg->data, msg->len);</span><br><span> </span><br><span> ret = write(bfd->fd, msg->data, msg->len);</span><br><span> if (ret < msg->len)</span><br><span>@@ -476,9 +446,8 @@</span><br><span> return ret;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- if (0/*invertbits*/) {</span><br><span style="color: hsl(0, 100%, 40%);">- flip_buf_bits(msg->data, ret);</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(120, 100%, 40%);">+ if (0/*invertbits*/)</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_revbytebits_buf(msg->data, ret);</span><br><span> </span><br><span> msgb_put(msg, ret);</span><br><span> </span><br><span>@@ -763,8 +732,6 @@</span><br><span> </span><br><span> int e1inp_dahdi_init(void)</span><br><span> {</span><br><span style="color: hsl(0, 100%, 40%);">- init_flip_bits();</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span> /* register the driver with the core */</span><br><span> return e1inp_driver_register(&dahdi_driver);</span><br><span> }</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/libosmo-abis/+/19500">change 19500</a>. 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<div style="display:none"> Gerrit-Project: libosmo-abis </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I285a87a9fc6abae7d8b47923a46cd082f46829f8 </div>
<div style="display:none"> Gerrit-Change-Number: 19500 </div>
<div style="display:none"> Gerrit-PatchSet: 2 </div>
<div style="display:none"> Gerrit-Owner: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder </div>
<div style="display:none"> Gerrit-Reviewer: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-MessageType: merged </div>