include "../include/memory-map.txt"

# Read from serial port w/ remote echo. Ignores CRs.
#
# char read_char()
# {
#   uint32_t in;
#   char c;
#
#   do {
#     while (((in = *(uint32_t*)rs232_fifo) & 0x100) == 0)
#       /* wait for input */;
#     c = in & 0xff;
#   } while (c == '\r');
#
#   write_char(c);
#   return c;
# }

read_char:
   immed rs232_fifo
   load
   dup; immed 0x100; and
   jump .got_char rel ne drop
   jump read_char rel drop
.got_char:
   immed 0xff; and
   dup; immed 13; sub
   jump .ignore_cr rel eq drop
   dup
   call write_char
   return
.ignore_cr:
   jump read_char rel drop


write_char:
   dup; immed 10; sub
   jump .not_nl rel ne drop
   immed 13
   pushpc
.not_nl:
   immed rs232_status
   load byte; immed 2; and
   jump .not_nl rel ne drop
   immed rs232_fifo
   store byte
   return


newline:
   immed 10
   jump write_char
   # ^^^ Tail call