From: David Given <dg@cowlark.com>
Date: Sun, 19 May 2013 17:40:19 +0000 (+0100)
Subject: Add compare-and-branch instructions.
X-Git-Tag: release-6-0-pre-5~10^2~70
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=4f15423d63b7e35336aef1f2ebf2d2dc4bf24401;p=ack.git

Add compare-and-branch instructions.

--HG--
branch : dtrg-videocore
---

diff --git a/mach/vc4/as/mach1.c b/mach/vc4/as/mach1.c
index 6e7b6819f..440d7de97 100644
--- a/mach/vc4/as/mach1.c
+++ b/mach/vc4/as/mach1.c
@@ -19,3 +19,7 @@ extern void mem_instr(quad opcode, int cc, int rd, long offset, int rs);
 extern void mem_offset_instr(quad opcode, int cc, int rd, int qa, int rb);
 extern void mem_postincr_instr(quad opcode, int cc, int rd, int rs);
 extern void mem_address_instr(quad opcode, int rd, struct expr_t* expr);
+extern void branch_addcmp_reg_reg_instr(int cc, int rd, int ra, int rs, struct expr_t* expr);
+extern void branch_addcmp_lit_reg_instr(int cc, int rd, long va, int rs, struct expr_t* expr);
+extern void branch_addcmp_reg_lit_instr(int cc, int rd, int ra, long vs, struct expr_t* expr);
+extern void branch_addcmp_lit_lit_instr(int cc, int rd, long va, long vs, struct expr_t* expr);
diff --git a/mach/vc4/as/mach2.c b/mach/vc4/as/mach2.c
index 2abde7136..8143d080b 100644
--- a/mach/vc4/as/mach2.c
+++ b/mach/vc4/as/mach2.c
@@ -9,7 +9,7 @@
 %token <y_word> CC
 
 %token <y_word> OP
-%token <y_word> OP_BRANCH
+%token <y_word> OP_BRANCH OP_BRANCHLINK OP_ADDCMPB
 %token <y_word> OP_ONEREG
 %token <y_word> OP_ONELREG
 %token <y_word> OP_ALU
diff --git a/mach/vc4/as/mach3.c b/mach/vc4/as/mach3.c
index 64b503a98..aba49dca2 100644
--- a/mach/vc4/as/mach3.c
+++ b/mach/vc4/as/mach3.c
@@ -73,7 +73,8 @@
 0,     OP,                    B16(00000000,00001010),                  "rti",
 
 0,     OP_BRANCH,             0,                                       "b",
-0,     OP_BRANCH,             1,                                       "bl",
+0,     OP_BRANCHLINK,         0,                                       "bl",
+0,     OP_ADDCMPB,            0,                                       "addcmpb",
 
 0,     OP_ONELREG,            B16(00000000,10000000),                  "tbb",
 0,     OP_ONELREG,            B16(00000000,10100000),                  "tbs",
diff --git a/mach/vc4/as/mach4.c b/mach/vc4/as/mach4.c
index 78c9337c9..e9593e761 100644
--- a/mach/vc4/as/mach4.c
+++ b/mach/vc4/as/mach4.c
@@ -8,9 +8,26 @@
 operation
 	: OP                                   { emit2($1); }
 
-	| OP_BRANCH GPR                        { emit2($1 | ($2<<0)); }
-	| OP_BRANCH expr                       { branch_instr($1, ALWAYS, &$2); }
-	| OP_BRANCH CC expr                    { branch_instr($1, $2, &$3); }
+	| OP_BRANCH GPR                        { emit2(B16(00000000,01000000) | ($2<<0)); }
+	| OP_BRANCHLINK GPR                    { emit2(B16(00000000,01100000) | ($2<<0)); }
+
+	| OP_BRANCH expr                       { branch_instr(0, ALWAYS, &$2); }
+	| OP_BRANCHLINK expr                   { branch_instr(1, ALWAYS, &$2); }
+	| OP_BRANCH CC expr                    { branch_instr(0, $2, &$3); }
+	| OP_BRANCHLINK CC expr                { branch_instr(1, $2, &$3); }
+
+	| OP_BRANCH GPR ',' GPR ',' expr       { branch_addcmp_lit_reg_instr(ALWAYS, 0, $2, $4, &$6); }
+	| OP_BRANCH CC GPR ',' GPR ',' expr    { branch_addcmp_lit_reg_instr($2, 0, $3, $5, &$7); }
+	| OP_BRANCH GPR ',' '#' absexp ',' expr { branch_addcmp_lit_lit_instr(ALWAYS, 0, $2, $5, &$7); }
+	| OP_BRANCH CC GPR ',' '#' absexp ',' expr { branch_addcmp_lit_lit_instr($2, 0, $3, $6, &$8); }
+	| OP_ADDCMPB GPR ',' GPR ',' GPR ',' expr { branch_addcmp_reg_reg_instr(ALWAYS, $2, $4, $6, &$8); }
+	| OP_ADDCMPB CC GPR ',' GPR ',' GPR ',' expr { branch_addcmp_reg_reg_instr($2, $3, $5, $7, &$9); }
+	| OP_ADDCMPB GPR ',' '#' absexp ',' GPR ',' expr { branch_addcmp_reg_reg_instr(ALWAYS, $2, $5, $7, &$9); }
+	| OP_ADDCMPB CC GPR ',' '#' absexp ',' GPR ',' expr { branch_addcmp_reg_reg_instr($2, $3, $6, $8, &$10); }
+	| OP_ADDCMPB GPR ',' GPR ',' '#' absexp ',' expr { branch_addcmp_reg_lit_instr(ALWAYS, $2, $4, $7, &$9); }
+	| OP_ADDCMPB CC GPR ',' GPR ',' '#' absexp ',' expr { branch_addcmp_reg_lit_instr($2, $3, $5, $8, &$10); }
+	| OP_ADDCMPB GPR ',' '#' absexp ',' '#' absexp ',' expr { branch_addcmp_lit_lit_instr(ALWAYS, $2, $5, $8, &$10); }
+	| OP_ADDCMPB CC GPR ',' '#' absexp ',' '#' absexp ',' expr { branch_addcmp_lit_lit_instr($2, $3, $6, $9, &$11); }
 
 	| OP_ONELREG GPR
 	{
diff --git a/mach/vc4/as/mach5.c b/mach/vc4/as/mach5.c
index 265e18f52..768d2eaee 100644
--- a/mach/vc4/as/mach5.c
+++ b/mach/vc4/as/mach5.c
@@ -388,3 +388,87 @@ void mem_address_instr(quad opcode, int rd, struct expr_t* expr)
 	}
 }
 
+/* Common code for handling addcmp: merge in as much of expr as will fit to
+ * the second pair of the addcmp opcode. */
+
+static void branch_addcmp_common(quad opcode, int bits, struct expr_t* expr)
+{
+	quad type = expr->typ & S_TYP;
+
+	switch (pass)
+	{
+		case 0:
+			/* Calculate size of instructions only. */
+
+			emit2(0);
+			break;
+
+		case 1:
+		case 2:
+		{
+			if (type != DOTTYP)
+				serror("can't use this type of branch to jump outside the section");
+
+			/* The VC4 branch instructions express distance in 2-byte
+			 * words. */
+
+			int d = (expr->val - DOTVAL-2 + 4) / 2;
+
+			if (!fitx(d, bits))
+				serror("target of branch is too far away");
+
+			emit2(opcode | maskx(d, bits));
+			break;
+        }
+	}
+}
+
+void branch_addcmp_reg_reg_instr(int cc, int rd, int ra, int rs, struct expr_t* expr)
+{
+    if ((rd >= 0x10) || (ra >= 0x10) || (rs >= 0x10))
+        serror("can only use r0-r15 in this instruction");
+
+	emit2(B16(10000000,00000000) | (cc<<8) | (ra<<4) | (rd<<0));
+	branch_addcmp_common(B16(00000000,00000000) | (rs<<10), 10, expr);
+}
+
+void branch_addcmp_lit_reg_instr(int cc, int rd, long va, int rs, struct expr_t* expr)
+{
+    if ((rd >= 0x10) || (rs >= 0x10))
+        serror("can only use r0-r15 in this instruction");
+
+	if (!fitx(va, 4))
+		serror("value too big to encode into instruction");
+    va = maskx(va, 4);
+
+    emit2(B16(10000000,00000000) | (cc<<8) | (va<<4) | (rd<<0));
+    branch_addcmp_common(B16(01000000,00000000) | (rs<<10), 10, expr);
+}
+
+void branch_addcmp_reg_lit_instr(int cc, int rd, int ra, long vs, struct expr_t* expr)
+{
+    if ((rd >= 0x10) || (ra >= 0x10))
+        serror("can only use r0-r15 in this instruction");
+
+	if (!fitx(vs, 6))
+		serror("value too big to encode into instruction");
+	vs = maskx(vs, 6);
+
+	emit2(B16(10000000,00000000) | (cc<<8) | (ra<<4) | (rd<<0));
+	branch_addcmp_common(B16(10000000,00000000) | (vs<<8), 8, expr);
+}
+
+void branch_addcmp_lit_lit_instr(int cc, int rd, long va, long vs, struct expr_t* expr)
+{
+    if (rd >= 0x10)
+        serror("can only use r0-r15 in this instruction");
+
+	if (!fitx(va, 4) || !fitx(vs, 6))
+		serror("value too big to encode into instruction");
+	va = maskx(va, 4);
+	vs = maskx(vs, 6);
+
+	emit2(B16(10000000,00000000) | (cc<<8) | (va<<4) | (rd<<0));
+	branch_addcmp_common(B16(11000000,00000000) | (vs<<8), 8, expr);
+}
+
diff --git a/mach/vc4/test/opcodes.s b/mach/vc4/test/opcodes.s
index a2104fcd7..87a50d070 100644
--- a/mach/vc4/test/opcodes.s
+++ b/mach/vc4/test/opcodes.s
@@ -353,3 +353,10 @@ near:
 	ldb r0, main
 	stb r0, near
 	stb r0, main
+
+	b.eq r0, r1, near
+	b r0, r1, near
+	addcmpb r0, r1, r2, .
+	addcmpb r0, #1, r2, .
+	addcmpb r0, r1, #1, .
+	addcmpb r0, #1, #2, .