Add productions and attribute rules to the grammar of Figure 15.6 to handle Ada-style for loops. Using your modified grammar, hand-translate the syntax tree of Figure 15.10 into pseudo assembly notation. Keep the index variable and the upper loop bound in registers.

Figure 15.6:

Figure 15.10:

Transcribed Image Text:

reg_names : array [0..k-1] of register_name := ["r1", "r2" ..., "rk"] -- ordered set of temporaries program - stmt stmt.next.free_reg := 0 program.code := ["main:"] + stmt.code + ["goto exit"] while : stmt → expr stmtz stmtz expr.next.free_reg := stmt2.next.freereg := stmt.next.free_reg := stmtj.next.free_reg L1:= new.label(); L2 := new Jabel() stmtj.code := ["goto" L1] + [L2 ":"] + stmt2.code + [L1 ":"] + expr.code + ["if" expr.reg "goto" L2] + stmt3.code if : stmti → expr stmt2 stmt3 stmtą expr.next_free_reg := stmt2.next.free reg := stmt3.next.free_reg := stmtą.next_free_reg := stmtj.next-free-reg L1:= new.label(); L2 := newJabel() stmtj.code := expr.code + ["if" expr.reg "goto" L1] + stmtz.code + ["goto" L2] + [L1 ":"] + stmt2.code + [L2 ":"] + stmt4.code assign : stmtj → id expr stmtz expr.next.free_reg := stmt,.next.free. reg := stmtj.next.free_reg stmti.code := expr.code + [id.stpname ":=" expr.reg] + stmt2.code read : stmt → id, idz stmtz stmtj.code := ["al := &" id,.stp→name] + ["call" if id2.stp→type = int then "readint" else...] + [id2.stp-→name ":= rv"] + stmt2.code -- file write : stmtį + id expr stmt2 expr.next.free_reg := stmt2.next.free reg := stmtj.next.free_reg stmtj.code := ["a1 := &" id.stp→name] + ["a2 :=" expr.reg) + ["call" if id.stp→type int then "writeint" else..] + stmt2.code %3D -- file -- value writeln : stmtį + id stmtz stmtj.code := ["a1 := &" id.stpname] + ["call writeln"] + stmt2.code