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Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index c85e6db..7208f33 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -7581,7 +7581,7 @@ means there is no way to communicate to the compiler what is happening inside them. GCC has no visibility of symbols in the @code{asm} and may discard them as unreferenced. It also does not know about side effects of the assembler code, such as modifications to memory or registers. Unlike -some compilers, GCC assumes that no changes to either memory or registers +some compilers, GCC assumes that no changes to general purpose registers occur. This assumption may change in a future release. To avoid complications from future changes to the semantics and the @@ -7605,6 +7605,10 @@ all basic @code{asm} blocks use the assembler dialect specified by the Basic @code{asm} provides no mechanism to provide different assembler strings for different dialects. +For basic @code{asm} with non-empty assembler string GCC assumes +the assembler block does not change any general purpose registers, +but it may read or write any globally accessible variable. + Here is an example of basic @code{asm} for i386: @example |