"Sivaprasad.pv" <sivaprasad.pv@xxxxxxxxxxxxxxxxxx> writes: > I have little confusion about machine modes. > Initially our architecture supports both 16 & 32 bit registers. > At that time we have used > QImode - char > HImode - intergers (16 bit) > SImode - long interger(32 bit) > > Now we are proposed to change all registers to 32 bit registers.We > have corresponding load/store 8/16/32bit instructions available with > sign/zero extension. > Now any data item is represented as 32 bit value in registers. > Can I define a pattern with QImode / HImode/SImode (in .md file) or I > should use only SImode. You must define movqi and movhi, and you must define PROMOTE_MODE and/or LOAD_EXTEND_OP and/or provide sign- and zero-extension insns. Whether to define other QImode and HImode operations is optional, and depends on the instructions available on your processor. Ian
