Parameter

Description

Execution result (output)

0: Terminated normally

-1: EOF detected

File number (input)

Number that is returned when a file is opened

Beginning address of input buffer (input)

Beginning address of the buffer to which input data is written

_fcharget:

        MOV.L       R2,R5           ; Set the value of R2 (file number) in R5.

        MOV.L       #PARM,R2        ; Set the address of the parameter block in R2.

        MOV.L       R1,4h:5[R2] ; Set the value of R1 (input buffer) in R2 + 4 bytes.

        MOV.B       R5,1h:5[R2] ; Set the value of R5 in R2 + 1 bytes (file number).

        MOV.L       #01270000h,R1   ; Set the function code of FGETC in R1.

        MOV.L       #SIM_IO,R3      ; Set the address of the system call in R3.

        JSR         R3              ; System call

        NOP

        MOV.L       #PARM,R1  ; Set the address of the parameter block in R1.

        MOV.B       [R1],R1   ; Set the first byte of R1 (result of execution) in R1.

        RTS                   ; Return to the address where the function was called.

         .SECTION  B,DATA,ALIGN=4

PARM:       .BLKL   2               ; Parameter block area