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28 lines
660 B
ArmAsm
28 lines
660 B
ArmAsm
/* https://cirosantilli.com/linux-kernel-module-cheat#x86-cqto-and-cltq-instructions */
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#include <lkmc.h>
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LKMC_PROLOGUE
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/* CLTQ: top bit is zero: extend with zeroes. */
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mov $0x123456787FFFFFFF, %rax
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cltq
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LKMC_ASSERT_EQ(%rax, $0x000000007FFFFFFF)
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/* CLTQ: top bit is one: extend with ones. */
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mov $0x1234567880000000, %rax
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cltq
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LKMC_ASSERT_EQ(%rax, $0xFFFFFFFF80000000)
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/* CWTL: zeroes top 32-bits. */
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mov $0x123456789ABC8EF0, %rax
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cwtl
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LKMC_ASSERT_EQ(%rax, $0xFFFF8EF0)
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CWTL
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/* CBTW. */
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mov $0x123456789ABCDE80, %rax
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cbtw
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LKMC_ASSERT_EQ(%rax, $0x123456789ABCFF80)
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CWTL
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LKMC_EPILOGUE
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