[Mesa-dev] [PATCH 5/7] i965/disasm: Mark instructions that no longer exist in the opcode_desc tables.

[Francisco Jerez]

With this small addition we can now easily determine on which
generations a given instruction is supported from the opcode_desc
tables alone.
---
 src/mesa/drivers/dri/i965/brw_disasm.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_disasm.c b/src/mesa/drivers/dri/i965/brw_disasm.c
index 0125434..5c6f3e2 100644
--- a/src/mesa/drivers/dri/i965/brw_disasm.c
+++ b/src/mesa/drivers/dri/i965/brw_disasm.c
@@ -30,6 +30,14 @@
 #include "brw_inst.h"
 #include "brw_eu.h"
 
+/**
+ * Special opcode_desc entry that marks the instruction as no longer existing.
+ * Unless explicitly specified using this marker a hardware generation is
+ * assumed to have inherited all opcodes defined and not removed by previous
+ * generations.
+ */
+#define REMOVED { .name = "***removed***", .nsrc = ~0, .ndst = ~0 }
+
 static const struct opcode_desc gen4_opcode_descs[128] = {
    [BRW_OPCODE_MOV]      = { .name = "mov",     .nsrc = 1, .ndst = 1 },
    [BRW_OPCODE_FRC]      = { .name = "frc",     .nsrc = 1, .ndst = 1 },
@@ -94,6 +102,8 @@ static const struct opcode_desc gen6_opcode_descs[128] = {
    [BRW_OPCODE_MATH]     = { .name = "math",    .nsrc = 2, .ndst = 1 },
    [BRW_OPCODE_MAD]      = { .name = "mad",     .nsrc = 3, .ndst = 1 },
    [BRW_OPCODE_LRP]      = { .name = "lrp",     .nsrc = 3, .ndst = 1 },
+   [BRW_OPCODE_IFF]      = REMOVED,
+   [BRW_OPCODE_DO]       = REMOVED,
 };
 
 static const struct opcode_desc gen7_opcode_descs[128] = {
@@ -111,6 +121,8 @@ static const struct opcode_desc gen7_opcode_descs[128] = {
 };
 
 static const struct opcode_desc gen8_opcode_descs[128] = {
+   [BRW_OPCODE_F32TO16]  = REMOVED,
+   [BRW_OPCODE_F16TO32]  = REMOVED,
    [BRW_OPCODE_CSEL]     = { .name = "csel",    .nsrc = 3, .ndst = 1 },
 };
 
@@ -151,7 +163,6 @@ opcode_desc_table_for(const struct brw_device_info *devinfo, enum opcode opcode)
 
 /* Return the matching opcode_desc for the specified opcode number and
  * hardware generation, or NULL if the opcode is not supported by the device.
- * XXX -- Actually check whether the opcode is supported.
  */
 const struct opcode_desc *
 brw_opcode_desc(const struct brw_device_info *devinfo, enum opcode opcode)
@@ -159,7 +170,8 @@ brw_opcode_desc(const struct brw_device_info *devinfo, enum opcode opcode)
    const struct opcode_desc *opcode_descs =
       opcode_desc_table_for(devinfo, opcode);
 
-   if (opcode_descs)
+   if (opcode_descs && (opcode_descs[opcode].nsrc != ~0 &&
+                        opcode_descs[opcode].ndst != ~0))
       return &opcode_descs[opcode];
    else
       return NULL;
-- 
2.7.3