[jrdres]

As other commenters have said, C didn't actually generate fast programs for 8-bit processors, or even 16-bit processors for a long time. C is a poor fit for most of them, so assembly language was the only way to go.

A contemporary source is the opinionated "DTACK-Grounded" newsletter from 1981-1985. http://www.easy68k.com/paulrsm/dg/ Hal Hardenbergh raved about the fast 68000 chip and it's wonderfully easy assembly, but lamented that everyone switched to "portable" Pascal and C to write 16-bit programs so they seemed even slower than 8-bit ones. His favorite example was a direct comparison: Lotus 1-2-3, written in 8088 assembly, vs Context MBA with the same features but written in Pascal for portability. 1-2-3 was MUCH faster than Context on the PC, and no one remembers Context today. Or the $16,000 Unix-based AT&T workstation whose floating-point benchmarks are beaten by a $69 VIC-20. (Obviously due to the C-written runtime, which even followed the C standard of promoting all single precision calculations to double so single was no faster!)

His opinion of C was "slightly-disguised PDP/11 assembly". Not too bad for the 68000, but a terrible fit for the 8088 or Z80.