<
  "str" enterSubScope
  
  <
    # allocate an uninitialized string
    # 0 -> number of data bytes to allocate
    # 0 <- the string
    [[
      /rbx :popqReg

      /rdi :popqReg
      /rdi :pushqReg

      8 /rdi /rdi :movqMemDisp8Reg
      24 /rdi :addqImm8Reg
      ::internalAllocate /rax :movqImmReg
      /rax :callqReg

      # set type
      %10 7 /rax :orbImmMemDisp8

      # clear hash value
      /rdx /rdx :xorqRegReg
      /rdx 8 /rax :movqRegMemDisp8

      # set exact length
      /rdi :popqReg
      8 /rdi /rdi :movqMemDisp8Reg
      /rdi 16 /rax :movqRegMemDisp8

      /rax :pushqReg

      /rbx :pushqReg
      :retn
    ]] /eyalloc defv

    # reduce exact string length in place
    # 0 -> string to shorten
    # 1 -> length of prefix
    # 0 <- the same string (but now with exact length field overwritten)
    # this effectively creates a prefix of the string
    [[
      /rbx :popqReg

      /rax :popqReg
      /rcx :popqReg
      8 /rcx /rcx :movqMemDisp8Reg

      16 /rax /rcx :cmpqMemDisp8Reg
      /ok :jbeLbl8

      "prefix length above string length in inplacePrefix" ::outputError
      :ud2

      @ok
      /rcx 16 /rax :movqRegMemDisp8

      /rcx /rcx :xorqRegReg
      /rcx 8 /rax :movqRegMemDisp8 # reset hash value

      /rax :pushqReg

      /rbx :pushqReg
      :retn
    ]] /eyinplacePrefix defv

    # calculate a string infix
    # 0 -> string to shorten
    # 1 -> first position after the infix
    # 2 -> first position in the infix
    [[
      /rbx :popqReg

      /rcx :popqReg # rcx == string
      16 /rcx /rbp :movqMemDisp8Reg

      /rdi :popqReg
      8 /rdi /rdi :movqMemDisp8Reg
      0 /rdi :cmpqImm8Reg
      /positiveEndOffset :jgeLbl8
      /rbp /rdi :addqRegReg
      @positiveEndOffset

      /rsi :popqReg
      8 /rsi /rsi :movqMemDisp8Reg
      0 /rsi :cmpqImm8Reg
      /positiveStartOffset :jgeLbl8
      /rbp /rsi :addqRegReg
      @positiveStartOffset

      # rdi == end offset
      # rsi == start offset

      /rcx :pushqReg
      /rsi :pushqReg

      /rsi /rdi :subqRegReg
      /negativeLengthInfix :jsLbl8
      @negativeLengthInfixFixed

      /rdi :pushqReg
      ::internalAllocateString /rax :movqImmReg
      /rax :callqReg

      /rcx :popqReg # rcx == count of bytes to copy
      /rsi :popqReg # rsi == start offset
      /rdx :popqReg # rdx == source string

      /rax :pushqReg

      :cld
      /rcx /rcx :testqRegReg

      24 1 /rsi /rdx /rsi :leaqMemIndexScaleDisp8Reg
      24 /rax /rdi :leaqMemDisp8Reg
      :reprcx :movsb

      /rbx :pushqReg
      :retn

      @negativeLengthInfix
      /rdi /rdi :xorqRegReg
      /negativeLengthInfixFixed :jmpLbl8
    ]] /eyinfix defv

    # calculate a string prefix
    # 0 -> string to shorten
    # 1 -> first position after the prefix
    [[
      /rbx :popqReg

      /rcx :popqReg # rcx == string
      16 /rcx /rbp :movqMemDisp8Reg

      /rdi :popqReg
      8 /rdi /rdi :movqMemDisp8Reg
      0 /rdi :cmpqImm8Reg
      /positiveEndOffset :jgeLbl8
      /rbp /rdi :addqRegReg
      @positiveEndOffset

      /rsi /rsi :xorqRegReg

      # rdi == end offset
      # rsi == start offset

      /rcx :pushqReg
      /rsi :pushqReg

      /rsi /rdi :subqRegReg
      /negativeLengthInfix :jsLbl8
      @negativeLengthInfixFixed

      /rdi :pushqReg
      ::internalAllocateString /rax :movqImmReg
      /rax :callqReg

      /rcx :popqReg # rcx == count of bytes to copy
      /rsi :popqReg # rsi == start offset
      /rdx :popqReg # rdx == source string

      /rax :pushqReg

      :cld
      /rcx /rcx :testqRegReg

      24 1 /rsi /rdx /rsi :leaqMemIndexScaleDisp8Reg
      24 /rax /rdi :leaqMemDisp8Reg
      :reprcx :movsb

      /rbx :pushqReg
      :retn

      @negativeLengthInfix
      /rdi /rdi :xorqRegReg
      /negativeLengthInfixFixed :jmpLbl8
    ]] /eyprefix defv

    # calculate a string postfix
    # 0 -> string to shorten
    # 1 -> position of string where to start the postfix
    # 0 <- the requested postfix of the string
    [[
      /rbx :popqReg

      /rcx :popqReg # rcx == string
      16 /rcx /rbp :movqMemDisp8Reg

      /rbp /rdi :movqRegReg

      /rsi :popqReg
      8 /rsi /rsi :movqMemDisp8Reg
      0 /rsi :cmpqImm8Reg
      /positiveStartOffset :jgeLbl8
      /rbp /rsi :addqRegReg
      @positiveStartOffset

      # rdi == end offset
      # rsi == start offset

      /rcx :pushqReg
      /rsi :pushqReg

      /rsi /rdi :subqRegReg
      /negativeLengthInfix :jsLbl8
      @negativeLengthInfixFixed

      /rdi :pushqReg
      ::internalAllocateString /rax :movqImmReg
      /rax :callqReg

      /rcx :popqReg # rcx == count of bytes to copy
      /rsi :popqReg # rsi == start offset
      /rdx :popqReg # rdx == source string

      /rax :pushqReg

      :cld
      /rcx /rcx :testqRegReg

      24 1 /rsi /rdx /rsi :leaqMemIndexScaleDisp8Reg
      24 /rax /rdi :leaqMemDisp8Reg
      :reprcx :movsb

      /rbx :pushqReg
      :retn

      @negativeLengthInfix
      /rdi /rdi :xorqRegReg
      /negativeLengthInfixFixed :jmpLbl8
    ]] /eypostfix defv

    # produce a string from an integer array specifying its bytes
    # 0 -> array of integers
    # 0 <- the same bytes as a string
    [[
      /rbx :popqReg

      /rsi :popqReg
      /rsi :pushqReg
      /rsi /edi :movlMemReg # load array length
      3 /rdi :shrqImm8Reg
      /rdi :decqReg
      /rdi :pushqReg

      ::internalAllocateString /rax :movqImmReg
      /rax :callqReg

      /rcx :popqReg # number of characters to copy
      /rsi :popqReg
      8 /rsi :addqImm8Reg # move rsi to first array entry
      /rax :pushqReg # store target string on stack
      24 /rax :addqImm8Reg # move rax to first string byte

      @copyByte
      /rsi /rdx :movqMemReg # load object pointer
      8 /rdx /rdx :movqMemDisp8Reg # load integer value
      /dl /rax :movbRegMem

      8 /rsi :addqImm8Reg
      /rax :incqReg
      /copyByte :loopLbl8

      /rbx :pushqReg
      :retn
    ]] /eyfromArray defv
  > _ ==globalFunctions { defv }' ::allocateOffsetStruct

  [
    globalFunctions keys eydeff { | }' createScopeEntries
    createScopeExtensionEntries
  ] :execute

  leaveSubScope
> --

# vim: syn=elymas