Implements another size optimization (size down to 506 bytes)

Moves "wait_TXINI" up, right after "process_Host2Device", which allows us to get rid of an "rcall/ret" combo. Last call to "wait_TXINI' within "process_Host2Device" is now simply a fall-through.

Author: Rodrigo Torres

nanoBoot.S

@@ -976,8 +976,20 @@ process_Host2Device:
       ; Clear Transmitter Ready Flag
       rcall       clear_TXINI                   ; This function uses r17 to clear the TXINI bit in UEINTX
 
+      ; SIZE OPTIMIZATION: Fall through to wait_TXINI instead of rcall'ing it
       ; Wait for TXINI (OK to transmit)
-      rcall       wait_TXINI                    ; This function loads r17 with value of UEINTX
+      ; rcall       wait_TXINI                    ; This function loads r17 with value of UEINTX
+      ; ret                                       ; Return from call
+
+wait_TXINI:
+
+      ; NOTE: This function uses r17, we can use this fact to code other stuff
+      ; that happens before and after this functions is called
+
+      ; Wait for TXINI (OK to transmit)
+      ldd         r17, Y+oUEINTX                ; Load r17 with the value in the USB Endpoint Interrupt Register (UEINTX)
+      sbrs        r17, TXINI                    ; Check the value of bit TXINI in r17, skip the next instruction if set
+      rjmp        wait_TXINI                    ; Bit TXINI is not set, keep waiting
 
       ret                                       ; Return from call
 
@@ -1015,19 +1027,6 @@ clear_RXOUTI:
       ret                                       ; Return from call
 
 
-wait_TXINI:
-
-      ; NOTE: This function uses r17, we can use this fact to code other stuff
-      ; that happens before and after this functions is called
-
-      ; Wait for TXINI (OK to transmit)
-      ldd         r17, Y+oUEINTX                ; Load r17 with the value in the USB Endpoint Interrupt Register (UEINTX)
-      sbrs        r17, TXINI                    ; Check the value of bit TXINI in r17, skip the next instruction if set
-      rjmp        wait_TXINI                    ; Bit TXINI is not set, keep waiting
-
-      ret                                       ; Return from call
-
-
 wait_RXOUTI:
 
       ; NOTE: This function uses r17, we can use this fact to code other stuff