Fold LIBC_BITS into LIBC_INTRIN

libc/intrin/segmentation.h

@@ -0,0 +1,25 @@
+#ifndef COSMOPOLITAN_LIBC_BITS_SEGMENTATION_H_
+#define COSMOPOLITAN_LIBC_BITS_SEGMENTATION_H_
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
+
+/**
+ * Reads scalar from memory, offset by segment.
+ *
+ * @return *(MEM) relative to segment
+ * @see arch_prctl()
+ * @see pushpop()
+ */
+#define fs(MEM) __peek("fs", MEM)
+#define gs(MEM) __peek("gs", MEM)
+
+#define __peek(SEGMENT, ADDRESS)                                  \
+  ({                                                              \
+    typeof(*(ADDRESS)) Pk;                                        \
+    asm("mov\t%%" SEGMENT ":%1,%0" : "=r"(Pk) : "m"(*(ADDRESS))); \
+    Pk;                                                           \
+  })
+
+#endif /* __GNUC__ && !__STRICT_ANSI__ */
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_BITS_SEGMENTATION_H_ */