diff options
| -rw-r--r-- | kernel/console.c | 19 | ||||
| -rw-r--r-- | kernel/trap.c | 4 | ||||
| -rw-r--r-- | kernel/uart.c | 4 |
3 files changed, 20 insertions, 7 deletions
diff --git a/kernel/console.c b/kernel/console.c index 650e2af..6fb79cd 100644 --- a/kernel/console.c +++ b/kernel/console.c @@ -39,7 +39,7 @@ consputc(int c) } if(c == BACKSPACE){ - // if the user typed backspace, erase the character. + // if the user typed backspace, overwrite with a space. uartputc('\b'); uartputc(' '); uartputc('\b'); } else { uartputc(c); @@ -134,10 +134,10 @@ consoleread(int user_dst, uint64 dst, int n) } // -// the uart interrupt handler, uartintr(), calls this -// for each input character. do erase/kill processing, -// append to cons.buf, wake up reader if a whole -// line has arrived. +// the console input interrupt handler. +// uartintr() calls this for input character. +// do erase/kill processing, append to cons.buf, +// wake up consoleread() if a whole line has arrived. // void consoleintr(int c) @@ -165,9 +165,16 @@ consoleintr(int c) default: if(c != 0 && cons.e-cons.r < INPUT_BUF){ c = (c == '\r') ? '\n' : c; - cons.buf[cons.e++ % INPUT_BUF] = c; + + // echo back to the user. consputc(c); + + // store for consumption by consoleread(). + cons.buf[cons.e++ % INPUT_BUF] = c; + if(c == '\n' || c == C('D') || cons.e == cons.r+INPUT_BUF){ + // wake up consoleread() if a whole line (or end-of-file) + // has arrived. cons.w = cons.e; wakeup(&cons.r); } diff --git a/kernel/trap.c b/kernel/trap.c index 53d86ca..ec57bed 100644 --- a/kernel/trap.c +++ b/kernel/trap.c @@ -180,7 +180,9 @@ devintr() if((scause & 0x8000000000000000L) && (scause & 0xff) == 9){ - // supervisor external interrupt, via PLIC. + // this is a supervisor external interrupt, via PLIC. + + // irq indicates which device interrupted. int irq = plic_claim(); if(irq == UART0_IRQ){ diff --git a/kernel/uart.c b/kernel/uart.c index b8dd664..ba66237 100644 --- a/kernel/uart.c +++ b/kernel/uart.c @@ -43,6 +43,7 @@ uartinit(void) *R(1) = 0x01; } +// write one output character to the UART. void uartputc(int c) { @@ -52,6 +53,8 @@ uartputc(int c) *R(0) = c; } +// read one input character from the UART. +// return -1 if none is waiting. int uartgetc(void) { @@ -63,6 +66,7 @@ uartgetc(void) } } +// trap.c calls here when the uart interrupts. void uartintr(void) { |