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+ positive number MOD power of 2 now done with AND instruction
* fix to division of positive numbers by power of 2 * the result of a MOD is left in EDX if possible
This commit is contained in:
Jonas Maebe
parent
26fa893ed7
commit
89405ceeed
@ -53,11 +53,14 @@ implementation
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procedure secondmoddiv(var p : ptree);
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var
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hreg1 : tregister;
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pushed,popeax,popedx : boolean;
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shrdiv, andmod, pushed,popeax,popedx : boolean;
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power : longint;
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hl : plabel;
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begin
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shrdiv := false;
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andmod := false;
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secondpass(p^.left);
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set_location(p^.location,p^.left^.location);
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pushed:=maybe_push(p^.right^.registers32,p);
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@ -87,29 +90,46 @@ implementation
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if (p^.treetype=divn) and (p^.right^.treetype=ordconstn) and
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ispowerof2(p^.right^.value,power) then
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begin
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exprasmlist^.concat(new(pai386,op_reg_reg(A_OR,S_L,hreg1,hreg1)));
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getlabel(hl);
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emitjmp(C_NS,hl);
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if power=1 then
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exprasmlist^.concat(new(pai386,op_reg(A_INC,S_L,hreg1)))
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else
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exprasmlist^.concat(new(pai386,op_const_reg(A_ADD,S_L,p^.right^.value-1,hreg1)));
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emitlab(hl);
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exprasmlist^.concat(new(pai386,op_const_reg(A_SAR,S_L,power,hreg1)));
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end
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Begin
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shrdiv := true;
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{for signed numbers, the numerator must be adjusted before the
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shift instruction, but not wih unsigned numbers! Otherwise,
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"Cardinal($ffffffff) div 16" overflows! (JM)}
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If is_signed(p^.left^.resulttype) Then
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Begin
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exprasmlist^.concat(new(pai386,op_reg_reg(A_OR,S_L,hreg1,hreg1)));
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getlabel(hl);
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emitjmp(C_NS,hl);
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if power=1 then
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exprasmlist^.concat(new(pai386,op_reg(A_INC,S_L,hreg1)))
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else
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exprasmlist^.concat(new(pai386,op_const_reg(A_ADD,S_L,p^.right^.value-1,hreg1)));
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emitlab(hl);
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exprasmlist^.concat(new(pai386,op_const_reg(A_SAR,S_L,power,hreg1)));
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End
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Else
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exprasmlist^.concat(new(pai386,op_const_reg(A_SHR,S_L,power,hreg1)));
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End
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else
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if (p^.treetype=modn) and (p^.right^.treetype=ordconstn) and
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ispowerof2(p^.right^.value,power) and Not(is_signed(p^.left^.resulttype)) Then
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{is there a similar trick for MOD'ing signed numbers? (JM)}
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Begin
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exprasmlist^.concat(new(pai386,op_const_reg(A_AND,S_L,p^.right^.value-1,hreg1)));
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andmod := true;
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End
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else
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begin
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{ bring denominator to EDI }
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{ EDI is always free, it's }
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{ only used for temporary }
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{ purposes }
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if (p^.right^.location.loc<>LOC_REGISTER) and
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(p^.right^.location.loc<>LOC_CREGISTER) then
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begin
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del_reference(p^.right^.location.reference);
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p^.left^.location.loc:=LOC_REGISTER;
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exprasmlist^.concat(new(pai386,op_ref_reg(A_MOV,S_L,newreference(p^.right^.location.reference),R_EDI)));
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if (p^.right^.location.loc<>LOC_REGISTER) and
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(p^.right^.location.loc<>LOC_CREGISTER) then
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begin
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del_reference(p^.right^.location.reference);
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p^.left^.location.loc:=LOC_REGISTER;
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exprasmlist^.concat(new(pai386,op_ref_reg(A_MOV,S_L,newreference(p^.right^.location.reference),R_EDI)));
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end
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else
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begin
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@ -120,14 +140,14 @@ implementation
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popeax:=false;
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if hreg1=R_EDX then
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begin
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if not(R_EAX in unused) then
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if not(R_EAX in unused) then
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begin
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exprasmlist^.concat(new(pai386,op_reg(A_PUSH,S_L,R_EAX)));
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popeax:=true;
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end;
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emit_reg_reg(A_MOV,S_L,R_EDX,R_EAX);
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emit_reg_reg(A_MOV,S_L,R_EDX,R_EAX);
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end
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else
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else
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begin
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if not(R_EDX in unused) then
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begin
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@ -166,18 +186,47 @@ implementation
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end
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else
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if hreg1<>R_EAX then
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emit_reg_reg(A_MOV,S_L,R_EAX,hreg1);
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Begin
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ungetregister32(hreg1);
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hreg1 := getexplicitregister32(R_EAX);
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{ I don't think it's possible that now hreg1 <> R_EAX
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since popeax is false, but for all certainty I do
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support that situation (JM)}
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if hreg1 <> R_EAX then
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emit_reg_reg(A_MOV,S_L,R_EAX,hreg1);
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end;
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end
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else
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emit_reg_reg(A_MOV,S_L,R_EDX,hreg1);
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{if we did the mod by an "and", the result is in hreg1 and
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EDX certainly hasn't been pushed (JM)}
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if not(andmod) Then
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if popedx then
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{the mod was done by an (i)div (so the result is now in
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edx), but edx was occupied prior to the division, so
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move the result into a safe place (JM)}
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emit_reg_reg(A_MOV,S_L,R_EDX,hreg1)
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else
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Begin
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{Get rid of the unnecessary hreg1 if possible (same as with
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EAX in divn) (JM)}
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ungetregister32(hreg1);
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hreg1 := getexplicitregister32(R_EDX);
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if hreg1 <> R_EDX then
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emit_reg_reg(A_MOV,S_L,R_EDX,hreg1);;
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End;
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if popeax then
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exprasmlist^.concat(new(pai386,op_reg(A_POP,S_L,R_EAX)));
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if popedx then
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exprasmlist^.concat(new(pai386,op_reg(A_POP,S_L,R_EDX)));
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end;
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{ this registers are always used when div/mod are present }
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usedinproc:=usedinproc or ($80 shr byte(R_EAX));
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usedinproc:=usedinproc or ($80 shr byte(R_EDX));
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If not(andmod or shrdiv) then
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{andmod and shrdiv only use hreg1 (which is already in usedinproc,
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since it was acquired with getregister), the others also use both
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EAX and EDX (JM)}
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Begin
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usedinproc:=usedinproc or ($80 shr byte(R_EAX));
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usedinproc:=usedinproc or ($80 shr byte(R_EDX));
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End;
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clear_location(p^.location);
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p^.location.loc:=LOC_REGISTER;
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p^.location.register:=hreg1;
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@ -768,7 +817,12 @@ implementation
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end.
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{
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$Log$
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Revision 1.22 1999-05-01 13:24:11 peter
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Revision 1.23 1999-05-08 20:41:08 jonas
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+ positive number MOD power of 2 now done with AND instruction
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* fix to division of positive numbers by power of 2
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* the result of a MOD is left in EDX if possible
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Revision 1.22 1999/05/01 13:24:11 peter
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* merged nasm compiler
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* old asm moved to oldasm/
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