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authorQuentin Carbonneaux <quentin.carbonneaux@yale.edu>2015-08-18 17:19:08 -0400
committerQuentin Carbonneaux <quentin.carbonneaux@yale.edu>2015-09-15 23:01:31 -0400
commit17cba8793e759bd8b4a96bb1dc5b3fd51b7cde65 (patch)
tree84477456ea0eafcbfdc478eb1f310079f83d8540 /lisc/ABI
parentf8cd43adc4f95cecfaa7346f7fcdad98633f1b07 (diff)
downloadroux-17cba8793e759bd8b4a96bb1dc5b3fd51b7cde65.tar.gz
add comment about variadic functions in abi
Diffstat (limited to 'lisc/ABI')
-rw-r--r--lisc/ABI3
1 files changed, 3 insertions, 0 deletions
diff --git a/lisc/ABI b/lisc/ABI
index 735b631..d7088d4 100644
--- a/lisc/ABI
+++ b/lisc/ABI
@@ -36,6 +36,9 @@ Passing:
    on the stack.
  - When all registers are taken, write arguments on the
    stack from right to left.
+ - When calling a variadic function, %al stores the number
+   of vector registers used to pass arguments (it must be
+   an upper bound and does not have to be exact).
  - Registers %rbx, %r12 - %r15 are callee-save.
 
 Returning.