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bootasm.S: remove redundant A20 enable code

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chyyuu
2013-03-10 10:12:24 -04:00
parent 8a6deabc73
commit fe2e2c2f1d
2 changed files with 1 additions and 4 deletions
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code/lab1/boot/bootasm.S
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@@ -42,9 +42,6 @@ seta20.2:
movb $0xdf, %al # 0xdf -> port 0x60
outb %al, $0x60 # 0xdf = 11011111, means set P2's A20 bit(the 1 bit) to 1
movb $0xdf, %al # 0xdf -> port 0x60, do it again!
outb %al, $0x60 # 0xdf = 11011111, means set P2's A20 bit(the 1 bit) to 1
# Switch from real to protected mode, using a bootstrap GDT
# and segment translation that makes virtual addresses
# identical to physical addresses, so that the