From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:41124) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tck8N-0005ti-PT for qemu-devel@nongnu.org; Sun, 25 Nov 2012 16:53:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Tck8L-00011H-Ah for qemu-devel@nongnu.org; Sun, 25 Nov 2012 16:53:03 -0500 Received: from qmta07.emeryville.ca.mail.comcast.net ([76.96.30.64]:33325) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tck8L-00010f-4M for qemu-devel@nongnu.org; Sun, 25 Nov 2012 16:53:01 -0500 From: Matthew Ogilvie Date: Sun, 25 Nov 2012 14:51:42 -0700 Message-Id: <1353880306-8004-7-git-send-email-mmogilvi_qemu@miniinfo.net> In-Reply-To: <1353880306-8004-1-git-send-email-mmogilvi_qemu@miniinfo.net> References: <1353880306-8004-1-git-send-email-mmogilvi_qemu@miniinfo.net> Subject: [Qemu-devel] [PATCH v7 06/10] i8259: refactor pic_set_irq level logic List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Jan Kiszka , Matthew Ogilvie , "Maciej W. Rozycki" , Avi Kivity No change in functionality. Clarify that the only difference between level triggered and edge triggered interrupts is on the leading edge. Signed-off-by: Matthew Ogilvie --- hw/i8259.c | 26 +++++++++----------------- 1 file changed, 9 insertions(+), 17 deletions(-) diff --git a/hw/i8259.c b/hw/i8259.c index 95587cd..9b2ec40 100644 --- a/hw/i8259.c +++ b/hw/i8259.c @@ -140,26 +140,18 @@ static void pic_set_irq(void *opaque, int irq, int level) } #endif - if (s->elcr & mask) { - /* level triggered */ - if (level) { + if (level) { + if ((s->last_irr & mask) == 0 || /* edge for edge triggered */ + (s->elcr & mask)) { /* or level triggered */ s->irr |= mask; - s->last_irr |= mask; - } else { - s->irr &= ~mask; - s->last_irr &= ~mask; } + s->last_irr |= mask; } else { - /* edge triggered */ - if (level) { - if ((s->last_irr & mask) == 0) { - s->irr |= mask; - } - s->last_irr |= mask; - } else { - s->irr &= ~mask; - s->last_irr &= ~mask; - } + /* Dropping level clears the interrupt regardless of edge trigger + * vs level trigger. + */ + s->irr &= ~mask; + s->last_irr &= ~mask; } pic_update_irq(s); } -- 1.7.10.2.484.gcd07cc5