28 lines
903 B
QBasic
28 lines
903 B
QBasic
10 REM Test DEF SEG / PEEK / POKE
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20 REM --- Default segment: PEEK returns 0 ---
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30 PRINT "PEEK(0)="; PEEK(0)
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40 REM --- BIOS data area: video mode ---
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50 DEF SEG = &H40
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60 PRINT "VIDEO MODE="; PEEK(&H49)
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70 REM --- BIOS data area: columns ---
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80 PRINT "COLUMNS="; PEEK(&H4A)
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90 REM --- BIOS data area: timer ticks (low byte, just check it runs) ---
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100 T! = PEEK(&H6C)
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110 IF T! >= 0 THEN PRINT "TIMER TICKS OK" ELSE PRINT "TIMER TICKS FAIL"
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120 REM --- CGA text buffer: POKE a character (no TUI in piped mode) ---
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130 DEF SEG = &HB800
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140 POKE 0, 65
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150 REM In piped mode TUI is not active, so PEEK returns 0
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160 P = PEEK(0)
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170 PRINT "B800 PEEK="; P
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180 REM --- DEF SEG reset ---
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190 DEF SEG
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200 PRINT "RESET PEEK="; PEEK(0)
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210 REM --- Boundary values ---
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220 DEF SEG = 0
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230 PRINT "SEG 0 PEEK="; PEEK(0)
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240 DEF SEG = 65535
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250 PRINT "SEG FFFF PEEK="; PEEK(0)
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260 REM --- Done ---
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270 PRINT "DONE"
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