in the post below, I found that some people use as-hc08 from SDCC to assemble files for ST7 processors:
Has anybody tried to make a simple C program and compile it for ST7 ? How big effort will be to make SDCC port for ST7 ?
Honestly, I do not know neither ST7 nor HC08 architecture. But I recently found some ST7 pieces at home.
Vaclav - SDCC fan