From 8b718ee54b7cc1dc6423cadb4f471f0eba4e426e Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Mon, 24 Nov 1986 21:45:03 +0000
Subject: [PATCH] Initial revision

---
 mach/pdp/top/table | 104 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 mach/pdp/top/table

diff --git a/mach/pdp/top/table b/mach/pdp/top/table
new file mode 100644
index 000000000..2b4e433b3
--- /dev/null
+++ b/mach/pdp/top/table
@@ -0,0 +1,104 @@
+/* PDP-11 desciptor table for ACK target optimizer */
+
+/* Tunable constants: */
+
+MAXOP		2;
+LABEL_STARTER	'I';
+OPC_TERMINATOR	' ';
+
+%%;
+
+/* useful addressing modes: */
+
+ZERO		{strcmp(VAL,"$00") == 0			};
+ONE		{strcmp(VAL,"$01") == 0			};
+CONST		{VAL[0] == '$'				};	/* constant */
+A,B		{no_side_effects(VAL)			};
+X,Y		{TRUE					};
+REG		{is_register(VAL)			};	/* register */
+SREG		{is_scratchreg(VAL)			};	/* scratch reg */
+M_ONE		{strcmp(VAL,"$037777777777") == 0	};	/* -1	*/
+LAB,L1,L2	{VAL[0] == 'I'				};	/* label */
+
+%%;
+
+/* optimization patterns: */
+
+add ZERO,A  {carry_dead(REST)}	->	;
+add ONE, X  {carry_dead(REST)}	->	inc X;
+sub ONE, X  {carry_dead(REST)}	->	dec X;
+
+/* tst-elimination */
+tst (sp)+ : tst X		->	mov X,(sp)+;
+tst (sp)+ : mov X,-(sp) 	->	mov X,(sp);
+mov A,X : tst A			->	mov A,X;
+
+/* register subsumption */
+mov REG,A : ANY A,X 		->	mov REG,A : ANY REG,X;
+mov REG,A : ANY *A 		->	mov REG,A : ANY *REG;
+mov REG,A : ANY *A,X 		->	mov REG,A : ANY *REG,X;
+mov REG,A : ANY X,*A 		->	mov REG,A : ANY X,*REG;
+
+/* compare with -1 */
+cmp SREG,M_ONE : jeq LAB	->	inc SREG : jeq LAB;
+cmp SREG,M_ONE : jne LAB	->	inc SREG : jne LAB;
+
+/* skip over jump */
+jeq L1 : jbr L2: labdef L1	->	jne L2 : labdef L1;
+jge L1 : jbr L2: labdef L1	->	jlt L2 : labdef L1;
+jgt L1 : jbr L2: labdef L1	->	jle L2 : labdef L1;
+jlt L1 : jbr L2: labdef L1	->	jge L2 : labdef L1;
+jle L1 : jbr L2: labdef L1	->	jgt L2 : labdef L1;
+jne L1 : jbr L2: labdef L1	->	jeq L2 : labdef L1;
+
+/* byte-test */
+clr SREG : bisb X,SREG : tst SREG : jeq LAB
+				->	tstb X : jeq LAB;
+clr SREG : bisb X,SREG : tst SREG : jne LAB
+				->	tstb X : jne LAB;
+
+%%;
+
+/* auxiliary routines: */
+
+int no_side_effects(s)
+	register char *s;
+{
+
+	for(;;) {
+		switch(*s++) {
+			case '\0': return TRUE;
+			case '-':  if (*s == '(') return FALSE; break;
+			case ')':  if (*s == '+') return FALSE; break;
+		}
+	}
+	/* NOTREACHED */
+}
+
+int is_register(s)
+	register char *s;
+{
+	return *s++ == 'r' && *s >= '0' && *s <= '5';
+}
+
+int is_scratchreg(s)
+	register char *s;
+{
+	return *s++ == 'r' && (*s == '0' || *s == '1' || *s == '3');
+}
+
+int carry_dead(s)
+	char *s;
+{
+	switch(*s++) {
+		case 'a':	/* adc and adcb */
+			return *s++ != 'd' || *s != 'c';
+		case 'b':	/* bcc, bcs, bhi, bhis, blo, blos */
+			return *s != 'c' && *s != 'h' &&
+				(*s++ != 'l' || *s != 'o');
+		case 's':	/* sbc and sbcb */
+			return *s++ != 'b' || *s != 'c';
+		default:
+			return TRUE;
+	}
+}
-- 
2.34.1