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ibmpc: ringbuf optimization for c

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This commit is contained in:
tmk 2021-07-07 23:00:35 +09:00
parent 369b5cb21e
commit 7438f7baab
2 changed files with 18 additions and 9 deletions
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20
tmk_core/protocol/ibmpc.c
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@ -214,11 +214,10 @@ void ibmpc_host_isr_clear(void)
ringbuf_reset(&rb);
}
#define LO8(w) (*((uint8_t *)&(w)))
#define HI8(w) (*(((uint8_t *)&(w))+1))
// NOTE: With this ISR data line can be read within 2us after clock falling edge.
// To read data line early as possible:
// write naked ISR with asembly code to read the line and call C func to do other job?
// NOTE: With this ISR data line should be read within 5us after clock falling edge.
// Confirmed that ATmega32u4 can read data line in 2.5us from interrupt after
// ISR prologue pushs r18, r19, r20, r21, r24, r25 r30 and r31 with GCC 5.4.0
ISR(IBMPC_INT_VECT)
{
uint8_t dbit;
@ -366,16 +365,19 @@ ISR(IBMPC_INT_VECT)
DONE:
// store data
if (!ringbuf_put(&rb, isr_state & 0xFF)) {
// buffer overflow
ibmpc_error = IBMPC_ERR_FULL;
ringbuf_push(&rb, isr_state & 0xFF);
if (ringbuf_is_full(&rb)) {
// just became full
// Disable ISR if buffer is full
IBMPC_INT_OFF();
// inhibit: clock_lo
IBMPC_CLOCK_PORT &= ~(1<<IBMPC_CLOCK_BIT);
IBMPC_CLOCK_DDR |= (1<<IBMPC_CLOCK_BIT);
}
if (ringbuf_is_empty(&rb)) {
// buffer overflow
ibmpc_error = IBMPC_ERR_FULL;
}
ERROR:
// clear for next data
isr_state = 0x8000;