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Changes to word data update parity bit #16

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merged 2 commits into from
Mar 3, 2024
Merged

Changes to word data update parity bit #16

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38c80e0
Changes to word data update parity bit
mjhouse Mar 3, 2024
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mjhouse Mar 3, 2024
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59 changes: 49 additions & 10 deletions src/word/words.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,13 +2,19 @@ use crate::errors::{MessageError, SubsystemError, TerminalError};
use crate::fields::*;
use crate::flags::*;

macro_rules! parity {
( $t:ident ) => {
match $t.count_ones() % 2 {
0 => 1,
_ => 0,
}
};
/// Calculate a parity bit given a u16 word value
///
/// MIL STD 1553B uses an odd parity bit (1 if the
/// bit count of the data is even, 0 if not)[^1].
///
/// [^1]: [MIL-STD-1553 Tutorial](http://www.horntech.cn/techDocuments/MIL-STD-1553Tutorial.pdf)
#[inline]
#[must_use = "Result is not used"]
fn parity(v: u16) -> u8 {
match v.count_ones() % 2 {
0 => 1,
_ => 0,
}
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
Expand Down Expand Up @@ -44,7 +50,7 @@ impl CommandWord {
pub fn new(data: u16) -> Self {
Self {
data,
parity: parity!(data),
parity: parity(data),
}
}

Expand All @@ -62,6 +68,7 @@ impl CommandWord {
/// more information.
pub fn set_address(&mut self, value: Address) {
self.data = COMMAND_TERMINAL_ADDRESS_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the subaddress of this word
Expand All @@ -81,6 +88,7 @@ impl CommandWord {
/// more information.
pub fn set_subaddress(&mut self, value: SubAddress) {
self.data = COMMAND_SUBADDRESS_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the direction of transmission
Expand All @@ -97,6 +105,7 @@ impl CommandWord {
/// more information about this field.
pub fn set_transmit_receive(&mut self, value: TransmitReceive) {
self.data = COMMAND_TRANSMIT_RECEIVE_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the mode code of this word
Expand All @@ -120,6 +129,7 @@ impl CommandWord {
pub fn set_mode_code(&mut self, value: ModeCode) {
if self.is_mode_code() {
self.data = COMMAND_MODE_CODE_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}
}

Expand All @@ -146,6 +156,7 @@ impl CommandWord {
pub fn set_word_count(&mut self, value: u8) {
if !self.is_mode_code() {
self.data = COMMAND_WORD_COUNT_FIELD.set(self.data, value);
self.parity = parity(self.data);
}
}

Expand Down Expand Up @@ -214,7 +225,7 @@ impl StatusWord {
pub fn new(data: u16) -> Self {
Self {
data,
parity: parity!(data),
parity: parity(data),
}
}

Expand All @@ -232,6 +243,7 @@ impl StatusWord {
/// more information.
pub fn set_address(&mut self, value: Address) {
self.data = STATUS_TERMINAL_ADDRESS_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get Instrumentation flag of the status word
Expand All @@ -248,6 +260,7 @@ impl StatusWord {
/// more information.
pub fn set_instrumentation(&mut self, value: Instrumentation) {
self.data = STATUS_INSTRUMENTATION_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get Service Request flag of the status word
Expand All @@ -264,6 +277,7 @@ impl StatusWord {
/// more information.
pub fn set_service_request(&mut self, value: ServiceRequest) {
self.data = STATUS_SERVICE_REQUEST_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the value of the reserved portion of the status word
Expand All @@ -280,6 +294,7 @@ impl StatusWord {
/// more information.
pub fn set_reserved(&mut self, value: Reserved) {
self.data = STATUS_RESERVED_BITS_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the Broadcast Command flag from the status word
Expand All @@ -297,6 +312,7 @@ impl StatusWord {
/// more information.
pub fn set_broadcast_received(&mut self, value: BroadcastCommand) {
self.data = STATUS_BROADCAST_RECEIVED_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the Busy flag from the status word
Expand All @@ -314,6 +330,7 @@ impl StatusWord {
/// more information.
pub fn set_terminal_busy(&mut self, value: TerminalBusy) {
self.data = STATUS_TERMINAL_BUSY_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Get the Dynamic Bus Control Acceptance flag from the status word
Expand All @@ -331,6 +348,7 @@ impl StatusWord {
/// more information.
pub fn set_dynamic_bus_acceptance(&mut self, value: BusControlAccept) {
self.data = STATUS_DYNAMIC_BUS_ACCEPT_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Check if the message error flag is set
Expand All @@ -347,6 +365,7 @@ impl StatusWord {
/// more information.
pub fn set_message_error(&mut self, value: MessageError) {
self.data = STATUS_MESSAGE_ERROR_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Check if the subsystem error flag is set
Expand All @@ -363,6 +382,7 @@ impl StatusWord {
/// more information.
pub fn set_subsystem_error(&mut self, value: SubsystemError) {
self.data = STATUS_SUBSYSTEM_FLAG_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Check if the terminal error flag is set
Expand All @@ -379,6 +399,7 @@ impl StatusWord {
/// more information.
pub fn set_terminal_error(&mut self, value: TerminalError) {
self.data = STATUS_TERMINAL_FLAG_FIELD.set(self.data, value.into());
self.parity = parity(self.data);
}

/// Check if any of the various error flags are set
Expand Down Expand Up @@ -442,7 +463,7 @@ impl DataWord {
pub fn new(data: u16) -> Self {
Self {
data,
parity: parity!(data),
parity: parity(data),
}
}

Expand Down Expand Up @@ -470,6 +491,24 @@ impl DataWord {
mod tests {
use super::*;

#[test]
fn test_command_parity_update() {
let mut word = CommandWord::new(0b0000000000101010);
assert_eq!(word.parity,0);

word.set_address(Address::Value(0b00000001));
assert_eq!(word.parity,1);
}

#[test]
fn test_status_parity_update() {
let mut word = StatusWord::new(0b0000000010101010);
assert_eq!(word.parity,1);

word.set_address(Address::Value(0b00000001));
assert_eq!(word.parity,0);
}

#[test]
fn test_command_is_valid() {
let word = CommandWord::new(0b0000000000101010);
Expand Down