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+ optimized <dword> div <const dword>
git-svn-id: trunk@1993 -
This commit is contained in:
florian
parent
767291ca5f
commit
bec0daebfa
@ -80,7 +80,7 @@ implementation
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hl:Tasmlabel;
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op:Tasmop;
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e : longint;
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d,l,s,m,a : dword;
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d,l,r,s,m,a,n,t : dword;
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m_low,m_high,j,k : qword;
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begin
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secondpass(left);
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@ -144,78 +144,174 @@ implementation
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end
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else
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begin
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e:=tordconstnode(right).value;
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d:=abs(e);
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{ Determine algorithm (a), multiplier (m), and shift factor (s) for 32-bit
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signed integer division. Based on: Granlund, T.; Montgomery, P.L.:
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"Division by Invariant Integers using Multiplication". SIGPLAN Notices,
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Vol. 29, June 1994, page 61.
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}
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if is_signed(left.resulttype.def) then
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begin
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e:=tordconstnode(right).value;
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d:=abs(e);
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{ Determine algorithm (a), multiplier (m), and shift factor (s) for 32-bit
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signed integer division. Based on: Granlund, T.; Montgomery, P.L.:
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"Division by Invariant Integers using Multiplication". SIGPLAN Notices,
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Vol. 29, June 1994, page 61.
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}
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l:=log2(d);
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j:=qword($80000000) mod qword(d);
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k:=(qword(1) shl (32+l)) div (qword($80000000-j));
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m_low:=((qword(1)) shl (32+l)) div d;
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m_high:=(((qword(1)) shl (32+l)) + k) div d;
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while ((m_low shr 1) < (m_high shr 1)) and (l > 0) do
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begin
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m_low:=m_low shr 1;
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m_high:=m_high shr 1;
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dec(l);
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end;
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m:=m_high;
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s:=l;
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if (m_high shr 31)<>0 then
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a:=1
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else
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a:=0;
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cg.getcpuregister(exprasmlist,NR_EAX);
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emit_const_reg(A_MOV,S_L,aint(m),NR_EAX);
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cg.getcpuregister(exprasmlist,NR_EDX);
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emit_reg(A_IMUL,S_L,hreg1);
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emit_reg_reg(A_MOV,S_L,hreg1,NR_EAX);
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if a<>0 then
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begin
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l:=log2(d);
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j:=qword($80000000) mod qword(d);
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k:=(qword(1) shl (32+l)) div (qword($80000000-j));
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m_low:=((qword(1)) shl (32+l)) div d;
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m_high:=(((qword(1)) shl (32+l)) + k) div d;
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while ((m_low shr 1) < (m_high shr 1)) and (l > 0) do
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begin
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m_low:=m_low shr 1;
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m_high:=m_high shr 1;
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dec(l);
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end;
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m:=m_high;
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s:=l;
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if (m_high shr 31)<>0 then
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a:=1
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else
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a:=0;
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cg.getcpuregister(exprasmlist,NR_EAX);
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emit_const_reg(A_MOV,S_L,aint(m),NR_EAX);
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cg.getcpuregister(exprasmlist,NR_EDX);
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emit_reg(A_IMUL,S_L,hreg1);
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emit_reg_reg(A_MOV,S_L,hreg1,NR_EAX);
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if a<>0 then
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begin
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emit_reg_reg(A_ADD,S_L,NR_EAX,NR_EDX);
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{
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printf ("; dividend: memory location or register other than EAX or EDX\n");
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printf ("\n");
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printf ("MOV EAX, 0%08LXh\n", m);
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printf ("IMUL dividend\n");
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printf ("MOV EAX, dividend\n");
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printf ("ADD EDX, EAX\n");
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if (s) printf ("SAR EDX, %d\n", s);
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printf ("SHR EAX, 31\n");
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printf ("ADD EDX, EAX\n");
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if (e < 0) printf ("NEG EDX\n");
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printf ("\n");
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printf ("; quotient now in EDX\n");
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}
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end;
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{
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printf ("; dividend: memory location of register other than EAX or EDX\n");
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printf ("\n");
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printf ("MOV EAX, 0%08LXh\n", m);
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printf ("IMUL dividend\n");
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printf ("MOV EAX, dividend\n");
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if (s) printf ("SAR EDX, %d\n", s);
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printf ("SHR EAX, 31\n");
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printf ("ADD EDX, EAX\n");
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if (e < 0) printf ("NEG EDX\n");
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printf ("\n");
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printf ("; quotient now in EDX\n");
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}
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if s<>0 then
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emit_const_reg(A_SAR,S_L,s,NR_EDX);
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emit_const_reg(A_SHR,S_L,31,NR_EAX);
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emit_reg_reg(A_ADD,S_L,NR_EAX,NR_EDX);
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{
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printf ("; dividend: memory location or register other than EAX or EDX\n");
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printf ("\n");
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printf ("MOV EAX, 0%08LXh\n", m);
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printf ("IMUL dividend\n");
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printf ("MOV EAX, dividend\n");
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printf ("ADD EDX, EAX\n");
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if (s) printf ("SAR EDX, %d\n", s);
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printf ("SHR EAX, 31\n");
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printf ("ADD EDX, EAX\n");
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if (e < 0) printf ("NEG EDX\n");
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printf ("\n");
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printf ("; quotient now in EDX\n");
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}
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end;
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{
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printf ("; dividend: memory location of register other than EAX or EDX\n");
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printf ("\n");
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printf ("MOV EAX, 0%08LXh\n", m);
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printf ("IMUL dividend\n");
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printf ("MOV EAX, dividend\n");
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if (s) printf ("SAR EDX, %d\n", s);
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printf ("SHR EAX, 31\n");
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printf ("ADD EDX, EAX\n");
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if (e < 0) printf ("NEG EDX\n");
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printf ("\n");
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printf ("; quotient now in EDX\n");
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}
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if s<>0 then
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emit_const_reg(A_SAR,S_L,s,NR_EDX);
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emit_const_reg(A_SHR,S_L,31,NR_EAX);
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emit_reg_reg(A_ADD,S_L,NR_EAX,NR_EDX);
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if e<0 then
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emit_reg(A_NEG,S_L,NR_EDX);
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cg.ungetcpuregister(exprasmlist,NR_EDX);
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cg.ungetcpuregister(exprasmlist,NR_EAX);
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location.register:=cg.getintregister(exprasmlist,OS_INT);
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cg.a_load_reg_reg(exprasmlist,OS_INT,OS_INT,NR_EDX,location.register)
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end;
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if e<0 then
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emit_reg(A_NEG,S_L,NR_EDX);
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cg.ungetcpuregister(exprasmlist,NR_EDX);
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cg.ungetcpuregister(exprasmlist,NR_EAX);
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location.register:=cg.getintregister(exprasmlist,OS_INT);
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cg.a_load_reg_reg(exprasmlist,OS_INT,OS_INT,NR_EDX,location.register)
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end
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else
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begin
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d:=tordconstnode(right).value;
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if d>=$80000000 then
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begin
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emit_const_reg(A_CMP,S_L,d,hreg1);
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location.register:=cg.getintregister(exprasmlist,OS_INT);
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emit_const_reg(A_MOV,S_L,0,location.register);
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emit_const_reg(A_SBB,S_L,-1,location.register);
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end
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else
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begin
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{ Reduce divisor until it becomes odd }
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n:=0;
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t:=d;
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while (t and 1)=0 do
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begin
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t:=t shr 1;
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inc(n);
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end;
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{ Generate m, s for algorithm 0. Based on: Granlund, T.; Montgomery,
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P.L.: "Division by Invariant Integers using Multiplication".
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SIGPLAN Notices, Vol. 29, June 1994, page 61.
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}
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l:=log2(t)+1;
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j:=qword($ffffffff) mod qword(t);
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k:=(qword(1) shl (32+l)) div (qword($ffffffff-j));
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m_low:=((qword(1)) shl (32+l)) div t;
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m_high:=(((qword(1)) shl (32+l)) + k) div t;
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while ((m_low shr 1) < (m_high shr 1)) and (l>0) do
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begin
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m_low:=m_low shr 1;
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m_high:=m_high shr 1;
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l:=l-1;
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end;
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if (m_high shr 32)=0 then
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begin
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m:=dword(m_high);
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s:=l;
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a:=0;
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end
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{ Generate m, s for algorithm 1. Based on: Magenheimer, D.J.; et al:
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"Integer Multiplication and Division on the HP Precision Architecture".
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IEEE Transactions on Computers, Vol 37, No. 8, August 1988, page 980.
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}
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else
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begin
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s:=log2(t);
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m_low:=(qword(1) shl (32+s)) div qword(t);
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r:=dword(((qword(1)) shl (32+s)) mod qword(t));
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if (r < ((t>>1)+1)) then
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m:=dword(m_low)
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else
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m:=dword(m_low)+1;
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a:=1;
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end;
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{ Reduce multiplier for either algorithm to smallest possible }
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while (m and 1)=0 do
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begin
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m:=m shr 1;
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dec(s);
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end;
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{ Adjust multiplier for reduction of even divisors }
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inc(s,n);
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cg.getcpuregister(exprasmlist,NR_EAX);
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emit_const_reg(A_MOV,S_L,aint(m),NR_EAX);
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cg.getcpuregister(exprasmlist,NR_EDX);
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emit_reg(A_MUL,S_L,hreg1);
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if a<>0 then
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begin
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{
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printf ("; dividend: register other than EAX or memory location\n");
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printf ("\n");
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printf ("MOV EAX, 0%08lXh\n", m);
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printf ("MUL dividend\n");
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printf ("ADD EAX, 0%08lXh\n", m);
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printf ("ADC EDX, 0\n");
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if (s) printf ("SHR EDX, %d\n", s);
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printf ("\n");
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printf ("; quotient now in EDX\n");
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}
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emit_const_reg(A_ADD,S_L,m,NR_EAX);
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emit_const_reg(A_ADC,S_L,0,NR_EDX);
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end;
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if s<>0 then
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emit_const_reg(A_SHR,S_L,s,NR_EDX);
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cg.ungetcpuregister(exprasmlist,NR_EDX);
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cg.ungetcpuregister(exprasmlist,NR_EAX);
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location.register:=cg.getintregister(exprasmlist,OS_INT);
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cg.a_load_reg_reg(exprasmlist,OS_INT,OS_INT,NR_EDX,location.register)
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end;
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end
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end
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end
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else
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begin
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@ -27,7 +27,7 @@ begin
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my_modulus := temp or ((not m) and mask1 and mask2);
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end;
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function i32_modulus(x, m : integer) : integer;
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function i32_modulus(x, m : integer) : integer;
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var
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temp : integer;
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begin
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@ -44,7 +44,7 @@ begin
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end;
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var
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i : integer;
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i : integer;
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j, k : longint;
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res, res2 : longint;
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@ -275,7 +275,7 @@ begin
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assert((y div 3) = (y div z), 'Wrong uint32 division by 3 for y=' + hexstr(y,sizeof(y)*2) + ' z=' + hexstr(z, sizeof(z)*2));
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end;
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writeln('Success.');
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write('positive uint32 modulus test (3)...');
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for i := -10000 to 10000 do begin
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y := random(high(integer));
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@ -321,7 +321,7 @@ begin
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end;
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writeln('Success.');
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write('positive uint32 division test...');
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for i := -10000 to 10000 do begin
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y := random(high(integer));
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@ -330,7 +330,7 @@ begin
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assert((y div 512) = (y div z), 'Wrong uint32 division by 512 for y=' + hexstr(y,sizeof(y)*2) + ' z=' + hexstr(z, sizeof(z)*2));
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end;
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writeln('Success.');
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write('positive uint32 modulus test...');
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for i := -10000 to 10000 do begin
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y := random(high(integer));
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@ -338,6 +338,25 @@ begin
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z := 512;
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assert((y mod 512) = (u32_modulus(y,z)), 'Wrong uint32 modulus by 512 for y=' + hexstr(y,sizeof(y)*2) + ' z=' + hexstr(z, sizeof(z)*2));
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end;
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writeln('Success.');
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writeln('Success.');
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{ extra test for div by constant optimization }
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write('positive uint32 division test...');
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for i := -10000 to 10000 do begin
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y := random(high(integer));
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if (random(2) = 1) then y := 2 * y;
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z := $deadbeef;
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assert((y div $deadbeef) = (y div z), 'Wrong uint32 division by $deadbeaf for y=' + hexstr(y,sizeof(y)*2) + ' z=' + hexstr(z, sizeof(z)*2));
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end;
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writeln('Success.');
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write('positive uint32 division test...');
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for i := -10000 to 10000 do begin
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y := random(high(integer));
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if (random(2) = 1) then y := 2 * y;
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z := $b16beef;
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assert((y div $b16beef) = (y div z), 'Wrong uint32 division by $b16beef for y=' + hexstr(y,sizeof(y)*2) + ' z=' + hexstr(z, sizeof(z)*2));
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end;
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writeln('Success.');
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end.
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