[newlib-cygwin] riscv: Map between ieeefp.h exception bits and RISC-V FCSR bits

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=5377a847764461493c620644f6530892344d1cdd

commit 5377a847764461493c620644f6530892344d1cdd
Author: Keith Packard <keithp@keithp.com>
Date:   Mon Jan 20 22:46:36 2020 -0800

    riscv: Map between ieeefp.h exception bits and RISC-V FCSR bits
    
    If we had architecture-specific exception bits, we could just set them
    to match the processor, but instead ieeefp.h is shared by all targets
    so we need to map between the public values and the register contents.
    
    Signed-off-by: Keith Packard <keithp@keithp.com>

Diff:
---
 newlib/libc/machine/riscv/ieeefp.c | 40 +++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/newlib/libc/machine/riscv/ieeefp.c b/newlib/libc/machine/riscv/ieeefp.c
index c458322..60ecacf 100644
--- a/newlib/libc/machine/riscv/ieeefp.c
+++ b/newlib/libc/machine/riscv/ieeefp.c
@@ -40,6 +40,40 @@ frm_fp_rnd (unsigned frm)
     }
 }
 
+static fp_except
+frm_fp_except (unsigned except)
+{
+  fp_except fp = 0;
+  if (except & (1 << 0))
+    fp |= FP_X_IMP;
+  if (except & (1 << 1))
+    fp |= FP_X_UFL;
+  if (except & (1 << 2))
+    fp |= FP_X_OFL;
+  if (except & (1 << 3))
+    fp |= FP_X_DX;
+  if (except & (1 << 4))
+    fp |= FP_X_INV;
+  return fp;
+}
+
+static unsigned
+frm_except(fp_except fp)
+{
+  unsigned except = 0;
+  if (fp & FP_X_IMP)
+    except |= (1 << 0);
+  if (fp & FP_X_UFL)
+    except |= (1 << 1);
+  if (fp & FP_X_OFL)
+    except |= (1 << 2);
+  if (fp & FP_X_DX)
+    except |= (1 << 3);
+  if (fp & FP_X_INV)
+    except |= (1 << 4);
+  return except;
+}
+
 #endif /* __riscv_flen */
 
 fp_except
@@ -63,7 +97,7 @@ fp_except
 fpgetsticky(void)
 {
 #ifdef __riscv_flen
-  return frsr () & 0x1f;
+  return frm_fp_except(frsr ());
 #else
   return 0;
 #endif /* __riscv_flen */
@@ -102,8 +136,8 @@ fpsetsticky(fp_except sticky)
 {
 #ifdef __riscv_flen
   unsigned fsr = frsr ();
-  fssr (sticky & 0x1f | fsr & ~0x1f);
-  return fsr & 0x1f;
+  fssr (frm_except(sticky) | (fsr & ~0x1f));
+  return frm_fp_except(fsr);
 #else
   return -1;
 #endif /* __riscv_flen */