Retro1.org codex

*DECK,EXZERO
          IDENT  ZERO 
          SPACE  4
**        ZERO - ZERO A BUFFER
* 
*         ZERO(LOC(BUFFER),SIZE) ;     (SYMPL CALL) 
* 
*         ENTRY BUFFER - LOCATION OF FIRST WORD OF BUFFER 
*                SIZE - WORD COUNT OF BUFFER
 
          ENTRY  ZERO 
 ZERO     BSS    1
          SB1    1
          SA2    A1+B1       GET LOC OF SIZE
          MX6    0
          SA2    X2          GET SIZE 
          ZR     X2,ZERO     EXIT IF ZERO 
          SA3    X1 
          SA6    X3          FIRST ADDRESS TO CLEAR 
          SB2    X2-1        RESIDUAL COUNT 
          EQ     B2,B0,ZERO       EXIT IF ONLY ONE
 ZERO.LP  SB2    B2-B1
          SA6    A6+B1
          NZ     B2,ZERO.LP 
          EQ     ZERO        DONE 
          END