Aligned

<..EQUATIONS of amsmath.sty..>
                                     \catcode‘\#=13 \catcode‘\!=6
 \def\reg:align!1!2{%
    <.inany@true.>  \inalign@true <.displaybreak@.>\intertext@
    \ifingather@\else\displ@y@\fi\Let@  \let\math@cr@@@\math@cr@@@align
    \ifxxat@\else \let\tag\tag@in@align \fi
    \let\label\label@in@display !1% set st@r
    \ifst@rred\else \global\@eqnswtrue  \fi   \measure@{!2}%
    \global\row@\z@ \tabskip\eqnshift@
    <.clean span.>%
    <.halign amsmath align.>}
                                     \catcode‘\#=6 \catcode‘\!=12
 -_-_-

<..equations of amsmath.sty..>+
                                     \catcode‘\#=13 \catcode‘\!=6
 \def\reg:start@aligned!1!2{%
    \savecolumn@
    \vcenter \bgroup
         \maxfields@!2\relax
         \ifnum\maxfields@>\m@ne
             \multiply\maxfields@\tw@
             \let\math@cr@@@\math@cr@@@alignedat
         \else
             \let\math@cr@@@\math@cr@@@aligned
         \fi
         \Let@ \chardef\dspbrk@context\@ne
         \default@tag
         \global\column@\z@
    <.halign amsmath aligned.>}
                                     \catcode‘\#=6 \catcode‘\!=12
 -_-_-

<..halign amsmath aligned..>
 \SaveMkHalignConf:g{start@aligned}\HRestore\noalign
 \MkHalign#{&\column@plus $\m@th\displaystyle{{\HCode{}}#}$%
            &\column@plus $\m@th\displaystyle{{\HCode{}}#}$}%
 -_-_-

<..equations of amsmath.sty..>+
 \def\al:gned#1{%
    \Configure{start@aligned}{\csname a:#1\endcsname}%
        {\csname b:#1\endcsname}{\csname c:#1\endcsname}%
        {\csname d:#1\endcsname}{\csname e:#1\endcsname}%
        {\csname f:#1\endcsname}\pic:MkHalign{#1}}
 \NewConfigure{start@aligned}{6}
 -_-_-

<..equations of amsmath.sty..>+
 \def\:tempc{\crcr\EndMkHalign
     \RecallMkHalignConfig \restorecolumn@
     \egroup  \b:start@aligned}
 \HLet\endaligned=\:tempc
 \def\:temp{%
   \let\@testopt\alignsafe@testopt
   \futurelet\:temp\aligned:a}
 \def\aligned:a{\ifx [\:temp \expandafter\aligned:b
    \else \def\:temp{\aligned:b[c]}\expandafter\:temp \fi}
 \def\aligned:b[#1]{%
    \al:gned{aligned}{#1}\m@ne}
 \HLet\aligned=\:temp
 \def\reg:aligned{\reg:start@aligned}
 \NewConfigure{aligned}{6}
 -_-_-

<..equations of amsmath.sty..>+
 \def\:temp{\futurelet\:temp\alignedat:a}
 \def\alignedat:a{\ifx [\:temp \expandafter\alignedat:b
    \else \def\:temp{\alignedat:b[c]}\expandafter\:temp \fi}
 \def\alignedat:b[#1]{%
     \let\@testopt\alignsafe@testopt
     \al:gned{alignedat}{#1}\m@ne}
 \HLet\alignedat=\:temp
 \def\reg:alignedat{\reg:start@aligned}
 \NewConfigure{alignedat}{6}
 -_-_-