sys: fix, work on DOS versions that clobber di in int 25h/26h #159
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Running on DR-DOS v7.03, the int 25h call zeroes di leading to a crash here when di is expected to preserve the stack pointer. So push di twice and pop it twice. The second pop always gets the saved sp, regardless of whether int 21h or int 25h/26h are used. Refer to SvarDOS/edrdos#57 (comment)
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Running on DR-DOS v7.03, the int 25h call zeroes di leading to a crash here when di is expected to preserve the stack pointer. So push di twice and pop it twice. The second pop always gets the saved sp, regardless of whether int 21h or int 25h/26h are used.
Refer to SvarDOS/edrdos#57 (comment)