58 lines
1.1 KiB
ArmAsm
58 lines
1.1 KiB
ArmAsm
# When trying (and failing) to instrument at the basic block level
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# I thought up a lot of corner-cases in the rep code. This tries
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# to catch some of them
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# Performance counters give us 8207 insns
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# 11 + 8*1024 + 3 = 8206
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.globl _start
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_start:
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cld # we want these to happen forward
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mov $0xfeb131978,%rax # value to store
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# test back-to-back rep/stosb's
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mov $1024,%rcx
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mov $buffer1, %rdi # set destination
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rep stosb # store 1024 times
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rep stosb # should store 0 times
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rep stosb # should store 0 times
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# test stosb where cx is 0
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xor %rcx,%rcx
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mov $buffer1, %rdi # set destination
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rep stosb # should not load at all
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# test rep inside of a loop
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mov $1024, %rbx
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rep_loop:
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mov $1024,%rcx
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mov $buffer1, %rdi # set destination
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rep stosb
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mov $1024,%rcx
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mov $buffer1, %rdi # set destination
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rep stosb
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dec %rbx
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jnz rep_loop
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#================================
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# Exit
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#================================
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exit:
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mov $60,%rax
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xor %rdi,%rdi # we return 0
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syscall # and exit
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.bss
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.lcomm buffer1, 16384
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