tools:iio:generic_buffer: sign-extend and shift data

Refactor process_scan() to handle signed and unsigned data, respect shifts
and the data mask for 2, 4 and 8 byte sized scan elements.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c
index 419e227..4cd2464 100644 (file)
--- a/tools/iio/generic_buffer.c
+++ b/tools/iio/generic_buffer.c
@@ -59,33 +59,80 @@ int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
        return bytes;
 }
 
-void print2byte(int input, struct iio_channel_info *info)
+void print2byte(uint16_t input, struct iio_channel_info *info)
 {
        /* First swap if incorrect endian */
        if (info->be)
-               input = be16toh((uint16_t)input);
+               input = be16toh(input);
        else
-               input = le16toh((uint16_t)input);
+               input = le16toh(input);
 
        /*
         * Shift before conversion to avoid sign extension
         * of left aligned data
         */
        input >>= info->shift;
+       input &= info->mask;
        if (info->is_signed) {
-               int16_t val = input;
+               int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
+                             (16 - info->bits_used);
+               printf("%05f ", ((float)val + info->offset) * info->scale);
+       } else {
+               printf("%05f ", ((float)input + info->offset) * info->scale);
+       }
+}
 
-               val &= (1 << info->bits_used) - 1;
-               val = (int16_t)(val << (16 - info->bits_used)) >>
-                       (16 - info->bits_used);
-               printf("%05f ", ((float)val + info->offset)*info->scale);
+void print4byte(uint32_t input, struct iio_channel_info *info)
+{
+       /* First swap if incorrect endian */
+       if (info->be)
+               input = be32toh(input);
+       else
+               input = le32toh(input);
+
+       /*
+        * Shift before conversion to avoid sign extension
+        * of left aligned data
+        */
+       input >>= info->shift;
+       input &= info->mask;
+       if (info->is_signed) {
+               int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
+                             (32 - info->bits_used);
+               printf("%05f ", ((float)val + info->offset) * info->scale);
        } else {
-               uint16_t val = input;
+               printf("%05f ", ((float)input + info->offset) * info->scale);
+       }
+}
 
-               val &= (1 << info->bits_used) - 1;
-               printf("%05f ", ((float)val + info->offset)*info->scale);
+void print8byte(uint64_t input, struct iio_channel_info *info)
+{
+       /* First swap if incorrect endian */
+       if (info->be)
+               input = be64toh(input);
+       else
+               input = le64toh(input);
+
+       /*
+        * Shift before conversion to avoid sign extension
+        * of left aligned data
+        */
+       input >>= info->shift;
+       input &= info->mask;
+       if (info->is_signed) {
+               int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
+                             (64 - info->bits_used);
+               /* special case for timestamp */
+               if (info->scale == 1.0f && info->offset == 0.0f)
+                       printf("%" PRId64 " ", val);
+               else
+                       printf("%05f ",
+                              ((float)val + info->offset) * info->scale);
+       } else {
+               printf("%05f ", ((float)input + info->offset) * info->scale);
        }
 }
+
 /**
  * process_scan() - print out the values in SI units
  * @data:              pointer to the start of the scan
@@ -108,32 +155,12 @@ void process_scan(char *data,
                                   &channels[k]);
                        break;
                case 4:
-                       if (!channels[k].is_signed) {
-                               uint32_t val = *(uint32_t *)
-                                       (data + channels[k].location);
-                               printf("%05f ", ((float)val +
-                                                channels[k].offset)*
-                                      channels[k].scale);
-
-                       }
+                       print4byte(*(uint32_t *)(data + channels[k].location),
+                                  &channels[k]);
                        break;
                case 8:
-                       if (channels[k].is_signed) {
-                               int64_t val = *(int64_t *)
-                                       (data +
-                                        channels[k].location);
-                               if ((val >> channels[k].bits_used) & 1)
-                                       val = (val & channels[k].mask) |
-                                               ~channels[k].mask;
-                               /* special case for timestamp */
-                               if (channels[k].scale == 1.0f &&
-                                   channels[k].offset == 0.0f)
-                                       printf("%" PRId64 " ", val);
-                               else
-                                       printf("%05f ", ((float)val +
-                                                        channels[k].offset)*
-                                              channels[k].scale);
-                       }
+                       print8byte(*(uint64_t *)(data + channels[k].location),
+                                  &channels[k]);
                        break;
                default:
                        break;