ffi: support 64 bit bitfields.

* ffi.c (struct txr_ffi_type): Replace unsigned mask member
with a union m which holds unsigned mask and 64-bit fmask (fat
mask).
(ffi_sbit_put, ffi_sbit_get, ffi_ubit_put, ffi_ubit_get):
Refer to m.mask.
(ffi_fat_sbit_put, ffi_fat_sbit_get, ffi_fat_ubit_put,
ffi_fat_ubit_get): New static functions.
(ffi_generic_fat_sbit_put, ffi_generic_fat_sbit_get,
ffi_generic_fat_ubit_put, ffi_generic_fat_ubit_get):
Likewise.
(make_ffi_type_struct, make_ffi_type_union): Set up fat
mask for bitfields that are wider than int.
(ffi_type_compile): Refer to m.mask for the int and unsigned
int based bitfields declared with sbit and ubit that don't
mention a type. The bit operator now allows int64 and uint64
to be valid types for a bitfield. In this case, the "fat"
get and put functions are selected which use 64 bit operations.
Thus there is no efficiency impact on non-fat bitfields which
continue to use code with 32 bit operands.

(ffi_offsetof): Use the bitfield flag in the member's type
structure to detect bitfields, rather than the mask.

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/017/ffi-misc.tl b/tests/017/ffi-misc.tl
index 1b729bbc..68f67b6f 100644
--- a/tests/017/ffi-misc.tl
+++ b/tests/017/ffi-misc.tl
@@ -94,3 +94,18 @@
 (mtest
   (ffi-put (new flex x #\a y "bcd") (ffi (struct flex))) #b'6162636400'
   (ffi-get #b'6162636400' (ffi (struct flex))) #S(flex x #\a y "bcd"))
+
+(defvarl %big-endian% (zerop [(ffi-put #x1 (ffi uint32)) 0]))
+
+(typedef foo
+  (struct foo
+    (x (bit 48 uint64))
+    (y (bit 16 uint64))))
+
+(if %big-endian%
+  (mtest
+    (ffi-put (new foo x 1 y 1) (ffi foo)) #b'0000000000010001'
+    (ffi-put (new foo x #xABCDFFFFB00B y #x1234) (ffi foo)) #b'ABCDFFFFB00B1234')
+  (mtest
+    (ffi-put (new foo x 1 y 1) (ffi foo)) #b'0100000000000100'
+    (ffi-put (new foo x #xABCDFFFFB00B y #x1234) (ffi foo)) #b'0BB0FFFFCDAB3412'))