.In .SH B. IMPLEMENTATION .SH B.1. Excerpts from the non-optimized EM_table .PP Even though the non-optimized version of the EM_table is relatively straight-forward, examples have never hurt anybody. One of the simplest instructions is the \*(Siloc\*(So, which appears in our EM_table as follows: .DS \f6 .TA 8 16 24 32 40 48 56 64 C_loc ==> "set $1, T1"; "dec 4, SP"; "st T1, [SP]". \f1 .DE Just as \*(SiSP\*(So is an alias for \*(Si%l0\*(So, \*(SiT1\*(So is an alias for \*(Si%g1\*(So. A little more complex is the \*(Siadi\*(So which performs integer addition. .DS \f6 C_adi ==> "ld [SP], T1"; "ld [SP+4], T2"; "add T1, T2, T3"; "st T3, [SP+4]; "inc 4, SP". \f1 .DE We could go on with even more complex instructions, but since that would not contribute to anything the reader is referred to the implementation for more details. .SH B.2. Excerpts from the optimized EM_table .PP The optimized EM_table uses the cache primitives mentioned in chapter 4. This means that the \*(Siloc\*(So this time appears as .DS \f6 C_loc ==> push_const($1). \f1 .DE The \*(Silol\*(So can now be written as .DS \f6 C_lol ==> push_reg(LB); inc_tos($1); push_const(4); C_los(4). \f1 .DE Due to the law of conservation of misery somebody has to do the dirty work. In this case, it is the \*(Silos\*(So. To show just a small part of the implementation of the \*(Silos\*(So: .DS \f6 C_los $1 == 4 ==> if (type_of_tos() == T_cst) { arith size; const_str_t n; size= pop_const(); if (size <= 4) { reg_t a; reg_t a; char *LD; switch (size) { case 1: LD = "ldub"; break; case 2: LD = "lduh"; break; case 4: LD = "ld"; break; default: arg_error("C_los", size); } a = pop_reg_c13(n); b = alloc_reg(); "$LD [$a+$n], $b"; push_reg(b); free_reg(a); } else ... \f1 .DE For the full implementation, the reader is again referred to the actual implementation. Just to show how other instructions are affected by the optimization we will show that implementation of the \*(Sitge\*(So instruction: .DS \f6 C_tge ==> { reg_t a; reg_t b; a = pop_reg(); b = alloc_reg(); " tst $a"; " bge,a 1f"; " mov 1, $b"; /* delay slot */ " set 0, $b"; "1:"; free_reg(a); push_reg(b); }. \f1 .DE .SH .bp CREDITS .PP In order of appearance: .TS center; r c l. Original idea - Dick Grune Design & implementation - Philip Homburg - Raymond Michiels Tutor - Dick Grune Assistant Tutor - Ceriel Jacobs Proofreading - Dick Grune - Hans van Eck .TE .SH REFERENCES .PP .[ $LIST$ .]