sparc.h (ASM_DECLARE_REGISTER_GLOBAL): Document .register declaration.

	* config/sparc/sparc.h (ASM_DECLARE_REGISTER_GLOBAL): Document
	.register declaration. Don't use variables with __ prefixes.

From-SVN: r30810

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 119a1dbabc241ba14a2a704e9670a8a5caf38b1f..2932e8c77819a650df4cf45d0c36ab892bedafb9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -23,6 +23,9 @@
        information after SUBREGs are eliminated by optimizations in
        this pass if PROMOTE_FUNCTION_RETURN.
 
+       * config/sparc/sparc.h (ASM_DECLARE_REGISTER_GLOBAL): Document
+       .register declaration. Don't use variables with __ prefixes.
+
 Mon Dec  6 12:24:52 1999  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
        * fold-const.c (optimize_bit_field_compare): Only use one mode

diff --git a/gcc/config/sparc/sparc.h b/gcc/config/sparc/sparc.h
index 28371f48691a2bd27c8b4d78c1130103431de66c..ade328a0b970821e75d599a0fdc37f5e0d0c5248 100644 (file)
--- a/gcc/config/sparc/sparc.h
+++ b/gcc/config/sparc/sparc.h
@@ -1834,25 +1834,38 @@ do {                                                                    \
 } while (0)
 
 /* Output the special assembly code needed to tell the assembler some
-   register is used as global register variable.  */
+   register is used as global register variable.  
+
+   SPARC 64bit psABI declares registers %g2 and %g3 as application
+   registers and %g6 and %g7 as OS registers.  Any object using them
+   should declare (for %g2/%g3 has to, for %g6/%g7 can) that it uses them
+   and how they are used (scratch or some global variable).
+   Linker will then refuse to link together objects which use those
+   registers incompatibly.
+
+   Unless the registers are used for scratch, two different global
+   registers cannot be declared to the same name, so in the unlikely
+   case of a global register variable occupying more than one register
+   we prefix the second and following registers with .gnu.part1. etc.  */
+
+extern char sparc_hard_reg_printed[8];
 
 #ifdef HAVE_AS_REGISTER_PSEUDO_OP
 #define ASM_DECLARE_REGISTER_GLOBAL(FILE, DECL, REGNO, NAME)           \
 do {                                                                   \
   if (TARGET_ARCH64)                                                   \
     {                                                                  \
-      int __end = HARD_REGNO_NREGS ((REGNO), DECL_MODE (decl)) + (REGNO); \
-      int __reg;                                                       \
-      extern char sparc_hard_reg_printed[8];                           \
-      for (__reg = (REGNO); __reg < 8 && __reg < __end; __reg++)       \
-       if ((__reg & ~1) == 2 || (__reg & ~1) == 6)                     \
+      int end = HARD_REGNO_NREGS ((REGNO), DECL_MODE (decl)) + (REGNO); \
+      int reg;                                                         \
+      for (reg = (REGNO); reg < 8 && reg < end; reg++)                 \
+       if ((reg & ~1) == 2 || (reg & ~1) == 6)                         \
          {                                                             \
-           if (__reg == (REGNO))                                       \
-             fprintf ((FILE), "\t.register\t%%g%d, %s\n", __reg, (NAME)); \
+           if (reg == (REGNO))                                         \
+             fprintf ((FILE), "\t.register\t%%g%d, %s\n", reg, (NAME)); \
            else                                                        \
              fprintf ((FILE), "\t.register\t%%g%d, .gnu.part%d.%s\n",  \
-                      __reg, __reg - (REGNO), (NAME));                 \
-           sparc_hard_reg_printed[__reg] = 1;                          \
+                      reg, reg - (REGNO), (NAME));                     \
+           sparc_hard_reg_printed[reg] = 1;                            \
          }                                                             \
     }                                                                  \
 } while (0)