altos: Make stdio 8-bit clean by making pollchar return int

We were stealing one value (0xff) in the return value from pollchar to
indicate 'not ready yet'. Instead of doing that, use the integer value
-1 and have pollchar return an int instead of a char. That
necessitated cleaning a few other bits to make sure that 0xff wouldn't
get promoted to -1 on accident.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/src/cc1111/ao_usb.c b/src/cc1111/ao_usb.c
index ce26e808..81e9074e 100644
--- a/src/cc1111/ao_usb.c
+++ b/src/cc1111/ao_usb.c
@@ -382,19 +382,19 @@ ao_usb_putchar(char c) __critical __reentrant
 		ao_usb_in_send();
 }
 
-char
+int
 ao_usb_pollchar(void) __critical
 {
-	char c;
+	uint8_t c;
 	if (ao_usb_out_bytes == 0) {
 		USBINDEX = AO_USB_OUT_EP;
 		if ((USBCSOL & USBCSOL_OUTPKT_RDY) == 0)
-			return AO_READ_AGAIN;
+			return -1;
 		ao_usb_out_bytes = (USBCNTH << 8) | USBCNTL;
 		if (ao_usb_out_bytes == 0) {
 			USBINDEX = AO_USB_OUT_EP;
 			USBCSOL &= ~USBCSOL_OUTPKT_RDY;
-			return AO_READ_AGAIN;
+			return -1;
 		}
 	}
 	--ao_usb_out_bytes;
@@ -409,9 +409,9 @@ ao_usb_pollchar(void) __critical
 char
 ao_usb_getchar(void) __critical
 {
-	char	c;
+	int	c;
 
-	while ((c = ao_usb_pollchar()) == AO_READ_AGAIN)
+	while ((c = ao_usb_pollchar()) == -1)
 		ao_sleep(&ao_stdin_ready);
 	return c;
 }