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From: "n dot pipenbrinck at cubic dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug inline-asm/37621] New: Missing documentation for x86 inline assembler modifiers Date: Tue, 23 Sep 2008 12:14:00 -0000 [thread overview] Message-ID: <bug-37621-16098@http.gcc.gnu.org/bugzilla/> (raw) I came across the following modifiers for inline assembler: asm ("rorw $8, %w0" : "=q" (y) : "0" (x)); asm ("xchg %b0, %h0" : "=q" (y) : "0" (x)); They work very well. No bug in the compiler itself, but I haven't found anything about them in the online documentation. Note: The %w0, %b0 and %h0 modifiers allows us to access thesub-registers of a 32 bit register. E.g. if %0 is EAX, %w0 becomes AX, %b0 becomes AL and %h0 becomes AH. -- Summary: Missing documentation for x86 inline assembler modifiers Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: minor Priority: P3 Component: inline-asm AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: n dot pipenbrinck at cubic dot org GCC host triplet: x86 GCC target triplet: x86 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37621
next reply other threads:[~2008-09-23 12:14 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-09-23 12:14 n dot pipenbrinck at cubic dot org [this message] 2008-09-24 0:36 ` [Bug inline-asm/37621] " pinskia at gcc dot gnu dot org 2008-09-24 17:44 ` dlenski at gmail dot com 2008-09-24 22:43 ` n dot pipenbrinck at cubic dot org
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