[PATCH 3/4] riscv: Map between ieeefp.h exception bits and RISC-V FCSR bits

[Keith Packard]

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>
---
 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 c45832280..60ecacfc2 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 */
-- 
2.25.0.rc1