[project @ 2005-04-05 09:38:00 by simonmar]

[ghc-hetmet.git] / ghc / includes / MachRegs.h

diff --git a/ghc/includes/MachRegs.h b/ghc/includes/MachRegs.h
index e929579..9a18812 100644 (file)
--- a/ghc/includes/MachRegs.h
+++ b/ghc/includes/MachRegs.h
@@ -264,20 +264,41 @@
                callee-saves
   %rax
   %rbx         YES
-  %rcx
-  %rdx         (seem to be used as arg regs on x86-64)
-  %rsi         (seem to be used as arg regs on x86-64)
-  %rdi         (seem to be used as arg regs on x86-64)
-  %rbp         YES
+  %rcx          arg reg, caller-saves
+  %rdx         arg reg, caller-saves
+  %rsi         arg reg, caller-saves
+  %rdi         arg reg, caller-saves
+  %rbp         YES (our *prime* register)
   %rsp         (unavailable - stack pointer)
-  %r8
-  %r9
-  %r10
-  %r11         
+  %r8           arg reg, caller-saves
+  %r9          arg reg, caller-saves
+  %r10          caller-saves
+  %r11         caller-saves
   %r12         YES
   %r13         YES
   %r14         YES
   %r15         YES
+
+  %xmm0-7       arg regs, caller-saves
+  %xmm8-15      caller-saves
+
+  A better reg mapping might be:
+
+      %rbp  Sp
+      %rbx  R1
+      %r8   R2
+      %r9   R3
+      %r10  R4
+      %r12  Hp
+      %r14  SpLim
+      %r15  HpLim
+      %xmm8-11   F1-F4
+      %xmm12-13  D1-D2
+
+  Use the caller-saves regs for Rn, because we don't always have to
+  save those (as opposed to Sp/Hp/SpLim etc. which always have to be
+  saved).
+
   --------------------------------------------------------------------------- */
 
 #if x86_64_REGS