The BBC's speed is one of its great advantages, but at times it is also a disadvantage, especially when listing programs to the screen. This routine provides an alternative to page mode or holding down CTRL+SHIFT.

It intercepts the OSWRCH vector, slowing down all printing to the screen. To change the speed, alter the contents of the address &70. A value of 0 gives more or less the usual speed, 255 slows it down the most.

10 A=&D00
20 FOR P=0 TO 3 STEP 3
30 P%=A
40 [OPT P
50 PHP:PHA:TXA
60 PHA:TYA:PHA
70 LDA&70:BEQ LI
80 TAX:LDY#0
90 .L0 NOP:NOP:DEY
100 BNE L0:DEX
110 BNE L0
120 .L1 PLA:TAY:PLA
130 TAX:PLA:PLP
140 JMP &E0A4
150 ]
160 NEXT
170 ?&20E=A MOD 256
180 ?&20F=A DIV 256

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