_charget: 
        MOV.L       #1210000h,R1    ; Set the function code of GETC in R1. 
        MOV.L       #IO_BUF,R2      ; Set the address of the input buffer in R2. 
        MOV.L       #PARM,R3        ; Set the address of the parameter block in R3. 
        MOV.L       R2,[R3]         ; Set the address of the input buffer in the  
                                    ; parameter block. 
        MOV.L       R3,R2           ; Set the value of R3 (address of the parameter  
                                    ; block) in R2. 
        MOV.L       #SIM_IO,R3      ; Set the address of the system call in R3. 
        JSR         R3              ; System call 
        MOV.L       #IO_BUF,R2      ; Set the address of the input buffer in R2. 
        MOVU.B      [R2],R1         ; Set the first byte of the input buffer  
                                    ; (acquired 1-byte character) in R1. 
        RTS                         ; Return to the address where the function was  
                                    ; called. 
  
         .SECTION  B,DATA,ALIGN=4 
PARM:       .BLKL   1               ; Parameter block area 
         .SECTION  B_1,DATA 
IO_BUF:     .BLKL   1               ; Input/output buffer 
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