i965: Add a bit of validation for some ISA restrictions in the docs.

src/mesa/drivers/dri/i965/brw_eu_emit.c

@@ -103,12 +103,80 @@ static void brw_set_dest( struct brw_instruction *insn,
    guess_execution_size(insn, dest);
 }
 
+static void
+validate_reg(struct brw_instruction *insn, struct brw_reg reg)
+{
+   int hstride_for_reg[] = {0, 1, 2, 4};
+   int vstride_for_reg[] = {0, 1, 2, 4, 8, 16, 32, 64, 128, 256};
+   int width_for_reg[] = {1, 2, 4, 8, 16};
+   int execsize_for_reg[] = {1, 2, 4, 8, 16};
+   int width, hstride, vstride, execsize;
+
+   if (reg.file == BRW_IMMEDIATE_VALUE)
+      return;
+
+   if (reg.file == BRW_ARCHITECTURE_REGISTER_FILE &&
+       reg.file == BRW_ARF_NULL)
+      return;
+
+   assert(reg.hstride >= 0 && reg.hstride < Elements(hstride_for_reg));
+   hstride = hstride_for_reg[reg.hstride];
+
+   if (reg.vstride == 0xf) {
+      vstride = -1;
+   } else {
+      assert(reg.vstride >= 0 && reg.vstride < Elements(vstride_for_reg));
+      vstride = vstride_for_reg[reg.vstride];
+   }
+
+   assert(reg.width >= 0 && reg.width < Elements(width_for_reg));
+   width = width_for_reg[reg.width];
+
+   assert(insn->header.execution_size >= 0 &&
+	  insn->header.execution_size < Elements(execsize_for_reg));
+   execsize = execsize_for_reg[insn->header.execution_size];
+
+   /* Restrictions from 3.3.10: Register Region Restrictions. */
+   /* 3. */
+   assert(execsize >= width);
+
+   /* 4. */
+   if (execsize == width && hstride != 0) {
+      assert(vstride == -1 || vstride == width * hstride);
+   }
+
+   /* 5. */
+   if (execsize == width && hstride == 0) {
+      /* no restriction on vstride. */
+   }
+
+   /* 6. */
+   if (width == 1) {
+      assert(hstride == 0);
+   }
+
+   /* 7. */
+   if (execsize == 1 && width == 1) {
+      assert(hstride == 0);
+      assert(vstride == 0);
+   }
+
+   /* 8. */
+   if (vstride == 0 && hstride == 0) {
+      assert(width == 1);
+   }
+
+   /* 10. Check destination issues. */
+}
+
 static void brw_set_src0( struct brw_instruction *insn,
                           struct brw_reg reg )
 {
    if (reg.type != BRW_ARCHITECTURE_REGISTER_FILE)
       assert(reg.nr < 128);
 
+   validate_reg(insn, reg);
+
    insn->bits1.da1.src0_reg_file = reg.file;
    insn->bits1.da1.src0_reg_type = reg.type;
    insn->bits2.da1.src0_abs = reg.abs;
@@ -184,6 +252,8 @@ void brw_set_src1( struct brw_instruction *insn,
 
    assert(reg.nr < 128);
 
+   validate_reg(insn, reg);
+
    insn->bits1.da1.src1_reg_file = reg.file;
    insn->bits1.da1.src1_reg_type = reg.type;
    insn->bits3.da1.src1_abs = reg.abs;