2.2.0 can target both the Zilog Z80 and the Nintendo Gameboy's Z80-like gbz80. The port is incomplete - long support is incomplete (mul, div and mod are unimplimented), and both float and bitfield support is missing, but apart from that the code generated is correct.
As always, the code is the authoritave reference - see z80/ralloc.c and z80/gen.c. The stack frame is similar to that generated by the IAR Z80 compiler. IX is used as the base pointer, HL is used as a temporary register, and BC and DE are available for holding varibles. IY is currently unusued. Return values are stored in HL. One bad side effect of using IX as the base pointer is that a functions stack frame is limited to 127 bytes - this will be fixed in a later version.bc