Siemens SDA5708

[Tabsoft]

I don't see any reason you couldn't use an 877.

You'll just have to adjust for the specific 877 hardware.
The test program only takes 1070 words of flash, so no problem there.

[Tabsoft]

You just have to be mindful of the size of the datatable.
As is, it takes 672 code words of space to store just the table.

There are ways to compress the table, but maybe for another discussion.