Routines
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50148: Redraw The Screen When Input Is Waiting
Used by the routine at UpdateScreenDisplay.
Returns at once when the input flag is clear. Otherwise it redraws the screen before the next key is taken.
50148 LD A,(40968) Return if the input is zero.
50151 AND A
50152 RET Z
50153 PUSH HL Keep the text position and point at the top row, with eight pixel lines to redraw.
50154 PUSH DE
50155 PUSH BC
50156 LD HL,16384
50159 LD B,8
50161 PUSH BC Keep the count and the row, call SetPrinterMotorSpeed, then step H to the next pixel row.
50162 PUSH HL
50163 CALL SetPrinterMotorSpeed
50166 POP HL
50167 INC H
50168 POP BC
50169 DJNZ 50161 Count the next pixel row and repeat from 50161.
50171 LD A,4 Take 4.
50173 OUT (251),A Stop the ZX Printer motor (port 251).
50175 POP BC Restore the saved count, the saved source and the saved pointer from the stack.
50176 POP DE
50177 POP HL
50178 RET Return.
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