[sim] integrated SoftFloat-3 with ISA sim; removed SoftFloat-2b

[riscv-isa-sim.git] / softfloat / s_estimateDiv128To64.cc

diff --git a/softfloat/s_estimateDiv128To64.cc b/softfloat/s_estimateDiv128To64.cc
new file mode 100755 (executable)
index 0000000..f8610a2
--- /dev/null
+++ b/softfloat/s_estimateDiv128To64.cc
@@ -0,0 +1,28 @@
+
+#include <stdint.h>
+#include "platform.h"
+#include "primitives.h"
+
+uint64_t softfloat_estimateDiv128To64( uint64_t a64, uint64_t a0, uint64_t b )
+{
+    uint32_t b32;
+    uint64_t z;
+    struct uint128 term, rem;
+    uint64_t rem32;
+
+    if ( b <= a64 ) return UINT64_C( 0xFFFFFFFFFFFFFFFF );
+    b32 = b>>32;
+    z = ( (uint64_t) b32<<32 <= a64 ) ? UINT64_C( 0xFFFFFFFF00000000 )
+            : ( a64 / b32 )<<32;
+    term = softfloat_mul64To128( b, z );
+    rem = softfloat_sub128( a64, a0, term.v64, term.v0 );
+    while ( UINT64_C( 0x8000000000000000 ) <= rem.v64 ) {
+        z -= UINT64_C( 0x100000000 );
+        rem = softfloat_add128( rem.v64, rem.v0, b32, (uint64_t) ( b<<32 ) );
+    }
+    rem32 = ( rem.v64<<32 ) | ( rem.v0>>32 );
+    z |= ( (uint64_t) b32<<32 <= rem32 ) ? 0xFFFFFFFF : rem32 / b32;
+    return z;
+
+}
+