Tidy up atomicity in timer.c and ring_buffer.h

Adopt the macros for saving/restoring the interrupt state
that are provided by the avr gcc environment.

Removing intialization of the timer value; this shaves off
a few bytes because globals are default initialized to zero.
master
Wez Furlong 2016-11-27 22:41:22 -08:00
parent 1585fc4b61
commit be4e75423a
2 changed files with 28 additions and 34 deletions

View File

@ -17,6 +17,7 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
#include <avr/io.h> #include <avr/io.h>
#include <avr/interrupt.h> #include <avr/interrupt.h>
#include <util/atomic.h>
#include <stdint.h> #include <stdint.h>
#include "timer_avr.h" #include "timer_avr.h"
#include "timer.h" #include "timer.h"
@ -24,7 +25,7 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
// counter resolution 1ms // counter resolution 1ms
// NOTE: union { uint32_t timer32; struct { uint16_t dummy; uint16_t timer16; }} // NOTE: union { uint32_t timer32; struct { uint16_t dummy; uint16_t timer16; }}
volatile uint32_t timer_count = 0; volatile uint32_t timer_count;
void timer_init(void) void timer_init(void)
{ {
@ -52,10 +53,9 @@ void timer_init(void)
inline inline
void timer_clear(void) void timer_clear(void)
{ {
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli();
timer_count = 0; timer_count = 0;
SREG = sreg; }
} }
inline inline
@ -63,10 +63,9 @@ uint16_t timer_read(void)
{ {
uint32_t t; uint32_t t;
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli(); t = timer_count;
t = timer_count; }
SREG = sreg;
return (t & 0xFFFF); return (t & 0xFFFF);
} }
@ -76,10 +75,9 @@ uint32_t timer_read32(void)
{ {
uint32_t t; uint32_t t;
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli(); t = timer_count;
t = timer_count; }
SREG = sreg;
return t; return t;
} }
@ -89,10 +87,9 @@ uint16_t timer_elapsed(uint16_t last)
{ {
uint32_t t; uint32_t t;
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli(); t = timer_count;
t = timer_count; }
SREG = sreg;
return TIMER_DIFF_16((t & 0xFFFF), last); return TIMER_DIFF_16((t & 0xFFFF), last);
} }
@ -102,10 +99,9 @@ uint32_t timer_elapsed32(uint32_t last)
{ {
uint32_t t; uint32_t t;
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli(); t = timer_count;
t = timer_count; }
SREG = sreg;
return TIMER_DIFF_32(t, last); return TIMER_DIFF_32(t, last);
} }

View File

@ -4,13 +4,13 @@
* Ring buffer to store scan codes from keyboard * Ring buffer to store scan codes from keyboard
*------------------------------------------------------------------*/ *------------------------------------------------------------------*/
#define RBUF_SIZE 32 #define RBUF_SIZE 32
#include <util/atomic.h>
static uint8_t rbuf[RBUF_SIZE]; static uint8_t rbuf[RBUF_SIZE];
static uint8_t rbuf_head = 0; static uint8_t rbuf_head = 0;
static uint8_t rbuf_tail = 0; static uint8_t rbuf_tail = 0;
static inline void rbuf_enqueue(uint8_t data) static inline void rbuf_enqueue(uint8_t data)
{ {
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli();
uint8_t next = (rbuf_head + 1) % RBUF_SIZE; uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
if (next != rbuf_tail) { if (next != rbuf_tail) {
rbuf[rbuf_head] = data; rbuf[rbuf_head] = data;
@ -18,36 +18,34 @@ static inline void rbuf_enqueue(uint8_t data)
} else { } else {
print("rbuf: full\n"); print("rbuf: full\n");
} }
SREG = sreg; }
} }
static inline uint8_t rbuf_dequeue(void) static inline uint8_t rbuf_dequeue(void)
{ {
uint8_t val = 0; uint8_t val = 0;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
uint8_t sreg = SREG;
cli();
if (rbuf_head != rbuf_tail) { if (rbuf_head != rbuf_tail) {
val = rbuf[rbuf_tail]; val = rbuf[rbuf_tail];
rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE; rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
} }
SREG = sreg; }
return val; return val;
} }
static inline bool rbuf_has_data(void) static inline bool rbuf_has_data(void)
{ {
uint8_t sreg = SREG; bool has_data;
cli(); ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
bool has_data = (rbuf_head != rbuf_tail); has_data = (rbuf_head != rbuf_tail);
SREG = sreg; }
return has_data; return has_data;
} }
static inline void rbuf_clear(void) static inline void rbuf_clear(void)
{ {
uint8_t sreg = SREG; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
cli();
rbuf_head = rbuf_tail = 0; rbuf_head = rbuf_tail = 0;
SREG = sreg; }
} }
#endif /* RING_BUFFER_H */ #endif /* RING_BUFFER_H */