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Fix: Handle underflow properly at subnormal/normal boundary #157

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Fix: Handle underflow properly at subnormal/normal boundary #157

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2 changes: 1 addition & 1 deletion vendor/openc910/C910_RTL_FACTORY/gen_rtl/vfdsu/rtl/ct_vfdsu_pack.v
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Original file line number Diff line number Diff line change
Expand Up @@ -404,7 +404,7 @@ assign ex4_rst_inf[63:0] = (vfdsu_ex4_double) ? ex4_doub_rst_inf[63:0] :
vfdsu_ex4_half ? ex4_half_rst_inf[63:0] : ex4_bfloat_rst_inf[63:0];


assign ex4_cor_uf = (vfdsu_ex4_uf && !ex4_denorm_potnt_norm || ex4_uf_plus)
assign ex4_cor_uf = (vfdsu_ex4_uf || ex4_denorm_potnt_norm || ex4_uf_plus)
&& vfdsu_ex4_nx;
assign ex4_cor_nx = vfdsu_ex4_nx
|| vfdsu_ex4_of
Expand Down
25 changes: 25 additions & 0 deletions vendor/patches/openc910/0001-Fix-Handle-underflow-properly-at-subnormal-normal-bo.patch
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
From 2412caed0dfad31332878410e78754880654c60b Mon Sep 17 00:00:00 2001
From: Ihsane TAHIR <[email protected]>
Date: Fri, 29 Aug 2025 13:51:02 +0200
Subject: [PATCH] Fix: Handle underflow properly at subnormal/normal boundary

---
.../openc910/C910_RTL_FACTORY/gen_rtl/vfdsu/rtl/ct_vfdsu_pack.v | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vendor/openc910/C910_RTL_FACTORY/gen_rtl/vfdsu/rtl/ct_vfdsu_pack.v b/vendor/openc910/C910_RTL_FACTORY/gen_rtl/vfdsu/rtl/ct_vfdsu_pack.v
index 681b77a..fe56ca0 100644
--- a/vendor/openc910/C910_RTL_FACTORY/gen_rtl/vfdsu/rtl/ct_vfdsu_pack.v
+++ b/vendor/openc910/C910_RTL_FACTORY/gen_rtl/vfdsu/rtl/ct_vfdsu_pack.v
@@ -404,7 +404,7 @@ assign ex4_rst_inf[63:0] = (vfdsu_ex4_double) ? ex4_doub_rst_inf[63:0] :
vfdsu_ex4_half ? ex4_half_rst_inf[63:0] : ex4_bfloat_rst_inf[63:0];


-assign ex4_cor_uf = (vfdsu_ex4_uf && !ex4_denorm_potnt_norm || ex4_uf_plus)
+assign ex4_cor_uf = (vfdsu_ex4_uf || ex4_denorm_potnt_norm || ex4_uf_plus)
&& vfdsu_ex4_nx;
assign ex4_cor_nx = vfdsu_ex4_nx
|| vfdsu_ex4_of
--
2.17.2