Added some notes on the w64 ABI.

Rev: nettle/x86_64/README:1.3

diff --git a/x86_64/README b/x86_64/README
index 11c2be1561e21dc70388c21688a2baef523a3187..8506b719ae9ec84d135bbcc880f202b33c860a0d 100644 (file)
--- a/x86_64/README
+++ b/x86_64/README
@@ -23,3 +23,31 @@ Registers    May be          Argument
 %r13           
 %r14           
 %r15           
+
+w64 ABI, according to
+http://msdn.microsoft.com/en-us/library/9z1stfyw.aspx:
+
+Registers      May be          Argument
+               clobbered       number
+
+%rax           Y
+%rbx           
+%rcx           Y               1
+%rdx           Y               2
+%rbp           
+%rsi
+%rdi
+%rsp           (SP)
+%r8            Y               3
+%r9            Y               4
+%r10           Y
+%r11           Y
+%r12           
+%r13           
+%r14           
+%r15           
+
+Additional arguments are passed on the stack. "backing store" on the
+stack for the four register arguments is also required. %xmm6 and
+%xmm7 are callee-saved. The "long" type is just 32 bits. Nettle
+currently does *NOT* support this ABI.