From ece6f7290f4966aa5aaa7b2898459badfa618c9f Mon Sep 17 00:00:00 2001
From: Eyck-Alexander Jentzsch <alex@minres.com>
Date: Sat, 8 Mar 2025 12:44:37 +0100
Subject: [PATCH] small bugfixes, adds some half point functionality

---
 src/vm/fp_functions.cpp | 35 ++++++++++++++++++++++-------------
 src/vm/fp_functions.h   |  2 ++
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/vm/fp_functions.cpp b/src/vm/fp_functions.cpp
index 20a6610..883b3b0 100644
--- a/src/vm/fp_functions.cpp
+++ b/src/vm/fp_functions.cpp
@@ -45,9 +45,13 @@ extern "C" {
 
 using this_t = uint8_t*;
 // this does not inlcude any reserved rm or the DYN rm, as DYN rm should be taken care of in the vm_impl
-const std::array<uint8_t, 6> rmm_map = {softfloat_round_near_even /*RNE*/,   softfloat_round_minMag /*RTZ*/,
-                                        softfloat_round_min /*RDN*/,         softfloat_round_max /*RUP?*/,
-                                        softfloat_round_near_maxMag /*RMM*/, softfloat_round_odd /*ROD*/};
+const std::array<uint8_t, 7> rmm_map = {softfloat_round_near_even /*RNE*/,
+                                        softfloat_round_minMag /*RTZ*/,
+                                        softfloat_round_min /*RDN*/,
+                                        softfloat_round_max /*RUP?*/,
+                                        softfloat_round_near_maxMag /*RMM*/,
+                                        0 /*reserved*/,
+                                        softfloat_round_odd /*ROD*/};
 
 const uint32_t quiet_nan32 = 0x7fC00000;
 
@@ -55,6 +59,14 @@ extern "C" {
 
 uint32_t fget_flags() { return softfloat_exceptionFlags & 0x1f; }
 
+uint16_t fsqrt_h(uint16_t v1, uint8_t mode) {
+    float16_t v1f{v1};
+    softfloat_roundingMode = rmm_map.at(mode);
+    softfloat_exceptionFlags = 0;
+    float16_t r = f16_sqrt(v1f);
+    return r.v;
+}
+
 uint16_t fclass_h(uint16_t v1) {
 
     float16_t a{v1};
@@ -238,15 +250,12 @@ uint32_t fclass_s(uint32_t v1) {
 }
 
 uint32_t fconv_d2f(uint64_t v1, uint8_t mode) {
-    bool isNan = isNaNF64UI(v1);
-    bool isSNaN = softfloat_isSigNaNF64UI(v1);
-    softfloat_roundingMode = rmm_map.at(mode);
-    softfloat_exceptionFlags = 0;
-    if(isNan) {
-        if(isSNaN)
-            softfloat_raiseFlags(softfloat_flag_invalid);
+    if(softfloat_isSigNaNF64UI(v1)) {
+        softfloat_raiseFlags(softfloat_flag_invalid);
         return defaultNaNF32UI;
     } else {
+        softfloat_roundingMode = rmm_map.at(mode);
+        softfloat_exceptionFlags = 0;
         float32_t res = f64_to_f32(float64_t{v1});
         return res.v;
     }
@@ -608,7 +617,7 @@ uint64_t frsqrt7_d(uint64_t v) {
     int exp = expF64UI(v);
     uint64_t sign = signF64UI(v);
     unsigned constexpr e = 11;
-    unsigned constexpr s = 58;
+    unsigned constexpr s = 52;
     return frsqrt7_general(s, e, sign, exp, sig, subnormal);
 }
 
@@ -726,14 +735,14 @@ uint32_t frec7_s(uint32_t v, uint8_t mode) {
 uint64_t frec7_d(uint64_t v, uint8_t mode) {
     bool subnormal = false;
     uint64_t ret_val = 0;
-    if(recip_check(fclass_s(v), subnormal, ret_val)) {
+    if(recip_check(fclass_d(v), subnormal, ret_val)) {
         return ret_val;
     }
     uint64_t sig = fracF64UI(v);
     int exp = expF64UI(v);
     uint64_t sign = signF64UI(v);
     unsigned constexpr e = 11;
-    unsigned constexpr s = 58;
+    unsigned constexpr s = 52;
     if(frec_general(ret_val, s, e, sign, exp, sig, subnormal, mode))
         softfloat_exceptionFlags |= (softfloat_flag_inexact | softfloat_flag_overflow);
     return ret_val;
diff --git a/src/vm/fp_functions.h b/src/vm/fp_functions.h
index 7c83668..3f634d3 100644
--- a/src/vm/fp_functions.h
+++ b/src/vm/fp_functions.h
@@ -39,6 +39,8 @@
 
 extern "C" {
 uint32_t fget_flags();
+uint16_t fsqrt_h(uint16_t v1, uint8_t mode);
+uint16_t fclass_h(uint16_t v1);
 uint16_t frsqrt7_h(uint16_t v);
 uint16_t frec7_h(uint16_t v, uint8_t mode);
 uint32_t fadd_s(uint32_t v1, uint32_t v2, uint8_t mode);