[Mesa-dev] [PATCH] gallium/tgsi: correct typo propagated from NV_vertex_program1_1

[Erik Faye-Lund]

In the specification text of NV_vertex_program1_1, the upper
limit of the RCC instruction is written as 1.884467e+19 in
scientific notation, but as 0x5F800000 in binary. But the binary
version translates to 1.84467e+19 rather than 1.884467e+19 in
scientific notation.

Since the lower-limit equals 2^-64 and the binary version equals
2^+64, let's assume the value in scientific notation is a typo
and implement this using the value from the binary version
instead.

Signed-off-by: Erik Faye-Lund <kusmabite at gmail.com>
---

I've also e-mailed NVIDIA's contact as listed in the specification,
but I haven't gotten any reply yet.

I think it's pretty obvious, though. I seriously doubt anyone
implemented the old limit, as it would require quite a bit more
gates AFAIK.

 src/gallium/auxiliary/tgsi/tgsi_exec.c | 8 ++++----
 src/gallium/docs/source/tgsi.rst       | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.c b/src/gallium/auxiliary/tgsi/tgsi_exec.c
index 3d37eaa..7d35aeb 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.c
@@ -915,8 +915,8 @@ micro_rcc(union tgsi_exec_channel *dst,
       float recip = 1.0f / src->f[i];
 
       if (recip > 0.0f) {
-         if (recip > 1.884467e+019f) {
-            dst->f[i] = 1.884467e+019f;
+         if (recip > 1.84467e+019f) {
+            dst->f[i] = 1.84467e+019f;
          }
          else if (recip < 5.42101e-020f) {
             dst->f[i] = 5.42101e-020f;
@@ -926,8 +926,8 @@ micro_rcc(union tgsi_exec_channel *dst,
          }
       }
       else {
-         if (recip < -1.884467e+019f) {
-            dst->f[i] = -1.884467e+019f;
+         if (recip < -1.84467e+019f) {
+            dst->f[i] = -1.84467e+019f;
          }
          else if (recip > -5.42101e-020f) {
             dst->f[i] = -5.42101e-020f;
diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index 0501aca..be42572 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -424,7 +424,7 @@ XXX cleanup on aisle three
 
 .. math::
 
-  dst = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
+  dst = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.84467e+019) : clamp(1 / src.x, -1.84467e+019, -5.42101e-020)
 
 
 .. opcode:: DPH - Homogeneous Dot Product
-- 
1.8.5.3