head     1.1;
branch   1.1.1;
access   ;
symbols  initial:1.1.1.1 diogenes:1.1.1;
locks    ; strict;
comment  @;; @;


1.1
date     2007.11.26.14.50.36;  author fellnhofer;  state Exp;
branches 1.1.1.1;
next     ;
commitid        122547a751ef4567;

1.1.1.1
date     2007.11.26.14.50.36;  author fellnhofer;  state Exp;
branches ;
next     ;
commitid        122547a751ef4567;


desc
@@



1.1
log
@Initial revision
@
text
@@@ l0 : temp
@@ l1 : constant 1
@@ l2 : current address for memwrites
@@ l3 : temp, holds the value received from uart
@@ h1 : toggle bit = 0 zero, when a full 16 Bit word was received
@@ h2 : holds the bitmask of the invalid instruction 0xffff = special with
@@ l4 : temp, used for branch condition

  ldi   l2, 0x80
  lsi   l2, 0x40     @@ start of user program
  
  ldi   h2, 0xff     
  lsi   h2, 0xff     @@ h2 = 0xffff  

  ldi   l1, 1        @@ constant 1
  ldi   h1, 0        @@ toggle bit (hi low)

1: @@ wait for byte
  ldi   l0, 0xc0     @@ uart status address
  ldio  l3, [l0]
  nop
  ldi   h0, 2        @@ uart data ready bit
  and   l4, l3, h0
  ldi   h0, 0xc1     @@ uart data address
  brz   l4, :1
  nop    
  

  ldio  l3, [h0]     @@ uart rcv
  nop
  xor	h1, h1, l1   @@ toggle state (16 bit Ready)
  stio  l3, [h0]     @@ uart echo (uart should be ready at this point)
  nop
  ldi   h0, 0x00
  stio  l3, [h0]     @@ leds echo
  nop
  brz   h1, :2  
  nop		     @@ hier könnte leds echo sein (nop wegen evtl.  Simulator bug)


  @@ olny first half (LSB) of instruction was received  
  mov   h3, l3	     @@ h3: holds 16-bit instr (here LSB are set)  
  brnz  h1, :1
  nop

2: @@ full 16-Bit instruction is ready
  lsi   l3, 0x00     @@ move received 8 bits
  or    h3, h3, l3   @@ merge the two instructionbytes 
  stio  l2, [h0]     @@ write instruction to programm-mem
  nop
  xor   l4, h3, h2   @@ check if the instruction writen to pmem is 0xffff  
  adi   l2, 1	     @@ increase program-write address	
  brnz  l4, :1
  nop

@@@@ programm loaded

@@ jump to begin of loaded program
  ldi   l0, 0x40
  nop
  jump  <l0>
  nop@


1.1.1.1
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@
@
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