> C and C++ are not a very thin abstraction over assembly language

We can argue the thinkness (or the thinness) of the abstraction until cows come home, but

  while (*dst++ = *src++) ;

is a direct abstraction over

  L1:
    movb @(r0)+, @(r1)+
    tstb (r0)
    bne L1

(assuming «src» and «dst» are both «char *» and addresses are loaded into «r1» and «r0» registers, consequently) in the PDP-11 architecture that C was designed on and for. The instruction sequence is exactly 4x 16 bit words long. As well as

  *ptr &= 1;

becoming

  and #1, (r0)

and being 2x 16 bit word instruction (assuming «ptr» is an «int *» and is loaded into «r0»). Pointer arithmetic and array design in C as we know them today was highly influenced by the addressing modes existing in the PDP-11 ISA, with many C abstractions having to a direct correspondence to specific sequences of PDP-11 instructions.

C++ is much less of a hardware abstraction, specifically when it comes to the higher level language features.