Display Signed Number in Base X

The following Redcode displays a signed number is a chosen number base:

dot     slt    @stack,    #1+CORESIZE/2
        sts.a  #45,       0
        slt    @stack,    #1+CORESIZE/2
        mul    #-1,       @stack
udot    mov.b  @stack,    <stack
        div.b  base,      >stack
        mod.b  base,      @stack
        slt    @stack,    #10
        add    #7,        @stack
        add    #48,       @stack
        add    #1,        udcount
        jmn    udot,      <stack
        add    #1,        stack
udloop  sts    >stack,    0
udcount djn    udloop,    #0

base    dat    10

Unfortunately, the code is pretty ugly. Can you suggest a more elegant solution?

Write Number (implemented using a data stack)

Here's an alternative version of the routine to display numbers using exMARS Stream's sts opcode. The code executes in 8x+1 cycles, where x is the number of digits. This implementation uses a data stack.

printd  mov.a  *stack,    {stack
        div.a  #10,       }stack
        mod.a  #10,       *stack
        add.a  #48,       *stack
        add    #1,        pcount
        jmn.a  printd,    {stack
        add.a  #1,        stack
ploop   sts.a  }stack,    0
pcount  djn    ploop,     #0

Hello World in Redcode

Here's the shortest "Hello, World!" program I could implement, written using the sts opcode which is available in exMARS Streams.

write   sts.a  hello,     0
        sts.b  }write,    0
        djn    write,     #7

hello   dat    72,        101
        dat    108,       108
        dat    111,       44
        dat    32,        87
        dat    111,       114
        dat    108,       100
        dat    33,        10

Write Number

Here's a short iterative routine to write a number to standard out. Although longer than the recursive algorithm, it avoids the need to maintain a data / return stack. 9x+1 cycles are required, where x is the number of digits.

The sts opcode is available in exMARS Streams.

writedec  mov    number,         temp
          jmp    _wdloop+1,      >_wdloop

_wdloop   mul    #10,            #0
          div    #10,            temp
          jmn    _wdloop,        temp

_wdprint  mov    number,         temp
          div.b  _wdloop,        temp
          add    #48,            temp
          sts    temp,           0
          mod.b  _wdloop,        number
          div    #10,            _wdloop
          jmn    _wdprint,       _wdloop