ref: c35217a1a61f795d312eede2f84faf59c7c06a3c
dir: /as/target/x80/proc.h/
enum args {
	AREG_AF = AMAX,
	AREG_A,
	AREG_F,
	AREG_BC,
	AREG_B,
	AREG_C,
	AREG_HL,
	AREG_H,
	AREG_L,
	AREG_DE,
	AREG_D,
	AREG_E,
	AREG_IX,
	AREG_IXL,
	AREG_IXH,
	AREG_IY,
	AREG_IYL,
	AREG_IYH,
	AREG_R,
	AREG_I,
	AREG_AF_,
	AREG_RCLASS,  /* register class for B, C, D, E, H, L and A */
	AREG_PCLASS,  /* register class for B, C, D, E, IXH, IXL and A */
	AREG_QCLASS,  /* register class for B, C, D, E, IYH, IYL and A */
	AINDER_HL,    /* (HL) */
};
extern int rclass(int reg);
extern int pclass(int reg);
extern int qclass(int reg);