According the the XCOFF document,
If
Then
XTY_SD
x_scnlen contains the csect length.
XTY_LD
x_scnlen contains the symbol table index of the containing csect.
XTY_CM
x_scnlen contains the csect length.
XTY_ER
x_scnlen contains 0.
Change the SectionLen member name to SectionOrLength is more reasonable .
s/it contains//g;
s/XTY_SD,XTY_CM/XTY_SD or XTY_CM/;
s/is XTY_ER/is XTY_ER/;