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authorBrian Paul <brianp@vmware.com>2010-03-04 09:45:34 -0700
committerBrian Paul <brianp@vmware.com>2010-03-04 10:53:26 -0700
commit6464d81e779e8c05ef96c9e5dab4422ff1f25464 (patch)
tree8df16f6ade2f0e5ba27ba3d0b88012976fe08ee9
parent7d230dae70e8caa67cc6bd7501f892d44c40a5d4 (diff)
gallivm: added lp_build_set_sign()
-rw-r--r--src/gallium/auxiliary/gallivm/lp_bld_arit.c35
-rw-r--r--src/gallium/auxiliary/gallivm/lp_bld_arit.h4
2 files changed, 39 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
index f60a7a213a..42ae9f6a22 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
@@ -718,6 +718,41 @@ lp_build_sgn(struct lp_build_context *bld,
/**
+ * Set the sign of float vector 'a' according to 'sign'.
+ * If sign==0, return abs(a).
+ * If sign==1, return -abs(a);
+ * Other values for sign produce undefined results.
+ */
+LLVMValueRef
+lp_build_set_sign(struct lp_build_context *bld,
+ LLVMValueRef a, LLVMValueRef sign)
+{
+ const struct lp_type type = bld->type;
+ LLVMTypeRef int_vec_type = lp_build_int_vec_type(type);
+ LLVMTypeRef vec_type = lp_build_vec_type(type);
+ LLVMValueRef shift = lp_build_int_const_scalar(type, type.width - 1);
+ LLVMValueRef mask = lp_build_int_const_scalar(type,
+ ~((unsigned long long) 1 << (type.width - 1)));
+ LLVMValueRef val, res;
+
+ assert(type.floating);
+
+ /* val = reinterpret_cast<int>(a) */
+ val = LLVMBuildBitCast(bld->builder, a, int_vec_type, "");
+ /* val = val & mask */
+ val = LLVMBuildAnd(bld->builder, val, mask, "");
+ /* sign = sign << shift */
+ sign = LLVMBuildShl(bld->builder, sign, shift, "");
+ /* res = val | sign */
+ res = LLVMBuildOr(bld->builder, val, sign, "");
+ /* res = reinterpret_cast<float>(res) */
+ res = LLVMBuildBitCast(bld->builder, res, vec_type, "");
+
+ return res;
+}
+
+
+/**
* Convert vector of int to vector of float.
*/
LLVMValueRef
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.h b/src/gallium/auxiliary/gallivm/lp_bld_arit.h
index 2d19ec06b4..866349d8cb 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.h
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.h
@@ -125,6 +125,10 @@ lp_build_sgn(struct lp_build_context *bld,
LLVMValueRef a);
LLVMValueRef
+lp_build_set_sign(struct lp_build_context *bld,
+ LLVMValueRef a, LLVMValueRef sign);
+
+LLVMValueRef
lp_build_int_to_float(struct lp_build_context *bld,
LLVMValueRef a);