rlc: Add and use mod_sns(bsn) method
Currently there is only a mod_sns() method which is being used in
expression like bsn_expr & win.mod_sns(). This only works, because
it is known that mod_sns() is (sns() - 1) where sns() in turn is
always 2^n. This is error prone, hard to read, and relies on window
specifics that should be kept inside the respective module.
This commit adds a mod_sns(uint bsn) method to gprs_rlc_ul_window and
gprs_rlc_dl_window, that encapsulates and hides this optimized
computation.
Sponsored-by: On-Waves ehf
diff --git a/src/tbf_ul.cpp b/src/tbf_ul.cpp
index 271f87a..cde361f 100644
--- a/src/tbf_ul.cpp
+++ b/src/tbf_ul.cpp
@@ -145,7 +145,6 @@
{
int8_t rssi = meas->have_rssi ? meas->rssi : 0;
- const uint16_t mod_sns = m_window.mod_sns();
const uint16_t ws = m_window.ws();
this->state_flags |= (1 << GPRS_RLCMAC_FLAG_UL_DATA);
@@ -194,7 +193,7 @@
LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d out of window "
"%d..%d (it's normal)\n", rdbi->bsn,
m_window.v_q(),
- (m_window.v_q() + ws - 1) & mod_sns);
+ m_window.mod_sns(m_window.v_q() + ws - 1));
} else if (m_window.is_received(rdbi->bsn)) {
LOGP(DRLCMACUL, LOGL_DEBUG,
"- BSN %d already received\n", rdbi->bsn);
@@ -219,7 +218,7 @@
LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d storing in window (%d..%d)\n",
rdbi->bsn, m_window.v_q(),
- (m_window.v_q() + ws - 1) & mod_sns);
+ m_window.mod_sns(m_window.v_q() + ws - 1));
block = m_rlc.block(rdbi->bsn);
block->block_info = *rdbi;
block->cs = rlc->cs;
@@ -296,7 +295,7 @@
/* Retrieve LLC frames from blocks that are ready */
for (uint16_t i = 0; i < count; ++i) {
- uint16_t index = (v_q_beg + i) & mod_sns;
+ uint16_t index = m_window.mod_sns(v_q_beg + i);
assemble_forward_llc(m_rlc.block(index));
}
@@ -304,7 +303,7 @@
if (this->state_is(GPRS_RLCMAC_FLOW) /* still in flow state */
&& this->m_window.v_q() == this->m_window.v_r()) { /* if complete */
struct gprs_rlc_data *block =
- m_rlc.block((m_window.v_r() - 1) & mod_sns);
+ m_rlc.block(m_window.mod_sns(m_window.v_r() - 1));
const struct gprs_rlc_ul_data_block_info *rdbi =
&block->block_info;