bug fix: cannot optimize IMUL

diff --git a/mach/i386/as/mach4.c b/mach/i386/as/mach4.c
index 7dda649..c5cb214 100644 (file)
--- a/mach/i386/as/mach4.c
+++ b/mach/i386/as/mach4.c
@@ -88,9 +88,9 @@ oper  :       NOOP_1
        |       IMUL    ea_2
                        {       reg_1 = IS_R32; imul(0); }
        |       IMUL    R32 ',' ea_2
-                       {       reg_1 = $2 | IS_R32; imul($2); }
+                       {       reg_1 = $2 | IS_R32; imul($2|0x10); }
        |       IMUL    R32 ',' ea_ea
-                       {       imul($2);}
+                       {       imul($2|0x10);}
        |       INT absexp
                        {       if ($2==3)
                                        emit1(0314);

diff --git a/mach/i386/as/mach5.c b/mach/i386/as/mach5.c
index 4a48333..a2370f8 100644 (file)
--- a/mach/i386/as/mach5.c
+++ b/mach/i386/as/mach5.c
@@ -507,23 +507,30 @@ imul(reg)
                if (exp_2.typ == S_ABS && fitb(exp_2.val)) {
                        /* case 1: 1 byte encoding of immediate */
                        emit1(0153);
-                       ea_1(reg << 3);
+                       ea_1((reg & 07) << 3);
                        emit1((int)(exp_2.val));
                }
                else {
                        /* case 2: WORD or DWORD encoding of immediate */
                        emit1(0151);
-                       ea_1(reg << 3);
+                       ea_1((reg & 07) << 3);
                        RELOMOVE(relonami, rel_2);
                        opsize_exp(exp_2, 1);
                }
        }
-       else if (is_reg(reg_1) && ((reg_1&7) == reg)) {
+       else if (is_reg(reg_1) && ((reg_1&7) == (reg & 07))) {
                /* the "reg" field and the "reg_or_mem" field are the same,
                   and the 3rd operand is not an immediate ...
                */
                if (reg == 0) {
                        /* how lucky we are, the target is the ax register */
+                       /* However, we cannot make an optimization for f.i.
+                               imul eax, blablabla
+                          because the latter does not affect edx, whereas
+                               imul blablabla
+                          does! Therefore, "reg" is or-ed with 0x10 in the
+                          former case, so that the test above fails.
+                       */
                        emit1(0367);
                        ea_2(050);
                }
@@ -531,7 +538,7 @@ imul(reg)
                        /* another register ... */
                        emit1(0xF);
                        emit1(0257);
-                       ea_2(reg << 3);
+                       ea_2((reg & 07) << 3);
                }
        }
        else badsyntax();