xref: /gem5/src/arch/x86/isa/insts/general_purpose/string/scan_string.py

# Copyright (c) 2007-2008 The Hewlett-Packard Development Company
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# Authors: Gabe Black

microcode = '''
def macroop SCAS_M {
    # Find the constant we need to either add or subtract from rdi
    ruflag t0, 10
    movi t2, t2, dsz, flags=(CEZF,), dataSize=asz
    subi t3, t0, dsz, dataSize=asz
    mov t2, t2, t3, flags=(nCEZF,), dataSize=asz

    ld t1, es, [1, t0, rdi]
    sub t0, rax, t1, flags=(OF, SF, ZF, AF, PF, CF)

    add rdi, rdi, t2, dataSize=asz
};

#
# Versions which have the rep prefix. These could benefit from some loop
# unrolling.
#

def macroop SCAS_E_M {
    and t0, rcx, rcx, flags=(EZF,), dataSize=asz
    br label("end"), flags=(CEZF,)

    # Find the constant we need to either add or subtract from rdi
    ruflag t0, 10
    movi t2, t2, dsz, flags=(CEZF,), dataSize=asz
    subi t3, t0, dsz, dataSize=asz
    mov t2, t2, t3, flags=(nCEZF,), dataSize=asz

topOfLoop:
    ld t1, es, [1, t0, rdi]
    sub t0, rax, t1, flags=(OF, SF, ZF, AF, PF, CF)

    subi rcx, rcx, 1, flags=(EZF,), dataSize=asz
    add rdi, rdi, t2, dataSize=asz
    br label("topOfLoop"), flags=(CSTRZnEZF,)
end:
    fault "NoFault"
};

def macroop SCAS_N_M {
    and t0, rcx, rcx, flags=(EZF,), dataSize=asz
    br label("end"), flags=(CEZF,)

    # Find the constant we need to either add or subtract from rdi
    ruflag t0, 10
    movi t2, t2, dsz, flags=(CEZF,), dataSize=asz
    subi t3, t0, dsz, dataSize=asz
    mov t2, t2, t3, flags=(nCEZF,), dataSize=asz

topOfLoop:
    ld t1, es, [1, t0, rdi]
    sub t0, rax, t1, flags=(OF, SF, ZF, AF, PF, CF)

    subi rcx, rcx, 1, flags=(EZF,), dataSize=asz
    add rdi, rdi, t2, dataSize=asz
    br label("topOfLoop"), flags=(CSTRnZnEZF,)
end:
    fault "NoFault"
};

'''