Mesa (master): gallivm: finish implementation of lp_build_iceil()
Brian Paul
brianp at kemper.freedesktop.org
Tue Jul 6 17:39:38 UTC 2010
Module: Mesa
Branch: master
Commit: e834c48100d9e373cb474b6dffa739769ac9ce42
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=e834c48100d9e373cb474b6dffa739769ac9ce42
Author: Brian Paul <brianp at vmware.com>
Date: Tue Jul 6 11:33:56 2010 -0600
gallivm: finish implementation of lp_build_iceil()
Plus fix minor error in lp_build_iceil() by tweaking the offset value.
And add a bunch of comments for the round(), trunc(), floor(), ceil()
functions.
---
src/gallium/auxiliary/gallivm/lp_bld_arit.c | 86 +++++++++++++++++++++------
1 files changed, 67 insertions(+), 19 deletions(-)
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
index d926b2d..3ceff86 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
@@ -847,6 +847,11 @@ lp_build_round_sse41(struct lp_build_context *bld,
}
+/**
+ * Return the integer part of a float (vector) value. The returned value is
+ * a float (vector).
+ * Ex: trunc(-1.5) = 1.0
+ */
LLVMValueRef
lp_build_trunc(struct lp_build_context *bld,
LLVMValueRef a)
@@ -869,6 +874,12 @@ lp_build_trunc(struct lp_build_context *bld,
}
+/**
+ * Return float (vector) rounded to nearest integer (vector). The returned
+ * value is a float (vector).
+ * Ex: round(0.9) = 1.0
+ * Ex: round(-1.5) = -2.0
+ */
LLVMValueRef
lp_build_round(struct lp_build_context *bld,
LLVMValueRef a)
@@ -890,6 +901,11 @@ lp_build_round(struct lp_build_context *bld,
}
+/**
+ * Return floor of float (vector), result is a float (vector)
+ * Ex: floor(1.1) = 1.0
+ * Ex: floor(-1.1) = -2.0
+ */
LLVMValueRef
lp_build_floor(struct lp_build_context *bld,
LLVMValueRef a)
@@ -911,6 +927,11 @@ lp_build_floor(struct lp_build_context *bld,
}
+/**
+ * Return ceiling of float (vector), returning float (vector).
+ * Ex: ceil( 1.1) = 2.0
+ * Ex: ceil(-1.1) = -1.0
+ */
LLVMValueRef
lp_build_ceil(struct lp_build_context *bld,
LLVMValueRef a)
@@ -933,7 +954,7 @@ lp_build_ceil(struct lp_build_context *bld,
/**
- * Return fractional part of 'a' computed as a - floor(f)
+ * Return fractional part of 'a' computed as a - floor(a)
* Typically used in texture coord arithmetic.
*/
LLVMValueRef
@@ -946,8 +967,9 @@ lp_build_fract(struct lp_build_context *bld,
/**
- * Convert to integer, through whichever rounding method that's fastest,
- * typically truncating toward zero.
+ * Return the integer part of a float (vector) value. The returned value is
+ * an integer (vector).
+ * Ex: itrunc(-1.5) = 1
*/
LLVMValueRef
lp_build_itrunc(struct lp_build_context *bld,
@@ -964,7 +986,10 @@ lp_build_itrunc(struct lp_build_context *bld,
/**
- * Convert float[] to int[] with round().
+ * Return float (vector) rounded to nearest integer (vector). The returned
+ * value is an integer (vector).
+ * Ex: iround(0.9) = 1
+ * Ex: iround(-1.5) = -2
*/
LLVMValueRef
lp_build_iround(struct lp_build_context *bld,
@@ -1007,7 +1032,9 @@ lp_build_iround(struct lp_build_context *bld,
/**
- * Convert float[] to int[] with floor().
+ * Return floor of float (vector), result is an int (vector)
+ * Ex: ifloor(1.1) = 1.0
+ * Ex: ifloor(-1.1) = -2.0
*/
LLVMValueRef
lp_build_ifloor(struct lp_build_context *bld,
@@ -1034,29 +1061,31 @@ lp_build_ifloor(struct lp_build_context *bld,
/* sign = a < 0 ? ~0 : 0 */
sign = LLVMBuildBitCast(bld->builder, a, int_vec_type, "");
sign = LLVMBuildAnd(bld->builder, sign, mask, "");
- sign = LLVMBuildAShr(bld->builder, sign, lp_build_const_int_vec(type, type.width - 1), "");
- lp_build_name(sign, "floor.sign");
+ sign = LLVMBuildAShr(bld->builder, sign, lp_build_const_int_vec(type, type.width - 1), "ifloor.sign");
/* offset = -0.99999(9)f */
- offset = lp_build_const_vec(type, -(double)(((unsigned long long)1 << mantissa) - 1)/((unsigned long long)1 << mantissa));
+ offset = lp_build_const_vec(type, -(double)(((unsigned long long)1 << mantissa) - 10)/((unsigned long long)1 << mantissa));
offset = LLVMConstBitCast(offset, int_vec_type);
- /* offset = a < 0 ? -0.99999(9)f : 0.0f */
+ /* offset = a < 0 ? offset : 0.0f */
offset = LLVMBuildAnd(bld->builder, offset, sign, "");
- offset = LLVMBuildBitCast(bld->builder, offset, vec_type, "");
- lp_build_name(offset, "floor.offset");
+ offset = LLVMBuildBitCast(bld->builder, offset, vec_type, "ifloor.offset");
- res = LLVMBuildAdd(bld->builder, a, offset, "");
- lp_build_name(res, "floor.res");
+ res = LLVMBuildAdd(bld->builder, a, offset, "ifloor.res");
}
- res = LLVMBuildFPToSI(bld->builder, res, int_vec_type, "");
- lp_build_name(res, "floor");
+ /* round to nearest (toward zero) */
+ res = LLVMBuildFPToSI(bld->builder, res, int_vec_type, "ifloor.res");
return res;
}
+/**
+ * Return ceiling of float (vector), returning int (vector).
+ * Ex: iceil( 1.1) = 2
+ * Ex: iceil(-1.1) = -1
+ */
LLVMValueRef
lp_build_iceil(struct lp_build_context *bld,
LLVMValueRef a)
@@ -1072,12 +1101,31 @@ lp_build_iceil(struct lp_build_context *bld,
res = lp_build_round_sse41(bld, a, LP_BUILD_ROUND_SSE41_CEIL);
}
else {
- /* TODO: mimic lp_build_ifloor() here */
- assert(0);
- res = bld->undef;
+ LLVMTypeRef vec_type = lp_build_vec_type(type);
+ unsigned mantissa = lp_mantissa(type);
+ LLVMValueRef mask = lp_build_const_int_vec(type, (unsigned long long)1 << (type.width - 1));
+ LLVMValueRef sign;
+ LLVMValueRef offset;
+
+ /* sign = a < 0 ? 0 : ~0 */
+ sign = LLVMBuildBitCast(bld->builder, a, int_vec_type, "");
+ sign = LLVMBuildAnd(bld->builder, sign, mask, "");
+ sign = LLVMBuildAShr(bld->builder, sign, lp_build_const_int_vec(type, type.width - 1), "iceil.sign");
+ sign = LLVMBuildNot(bld->builder, sign, "iceil.not");
+
+ /* offset = 0.99999(9)f */
+ offset = lp_build_const_vec(type, (double)(((unsigned long long)1 << mantissa) - 10)/((unsigned long long)1 << mantissa));
+ offset = LLVMConstBitCast(offset, int_vec_type);
+
+ /* offset = a < 0 ? 0.0 : offset */
+ offset = LLVMBuildAnd(bld->builder, offset, sign, "");
+ offset = LLVMBuildBitCast(bld->builder, offset, vec_type, "iceil.offset");
+
+ res = LLVMBuildAdd(bld->builder, a, offset, "iceil.res");
}
- res = LLVMBuildFPToSI(bld->builder, res, int_vec_type, "");
+ /* round to nearest (toward zero) */
+ res = LLVMBuildFPToSI(bld->builder, res, int_vec_type, "iceil.res");
return res;
}
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