From bd2a88840e2496e29442f333c8fdd6491e831a35 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 23 Mar 2015 15:29:27 +0000 Subject: [PATCH] Convert ffs() != 0 callers to ctz32() There are a number of ffs(3) callers that do roughly: bit = ffs(val); if (bit) { do_something(bit - 1); } This pattern can be converted to ctz32() like this: zeroes = ctz32(val); if (zeroes != 32) { do_something(zeroes); } Signed-off-by: Stefan Hajnoczi Message-id: 1427124571-28598-6-git-send-email-stefanha@redhat.com Signed-off-by: Kevin Wolf --- hw/arm/omap1.c | 6 ++---- hw/char/virtio-serial-bus.c | 8 ++++---- hw/gpio/omap_gpio.c | 13 +++++-------- hw/i2c/omap_i2c.c | 10 +++++++--- hw/intc/allwinner-a10-pic.c | 8 ++++---- kvm-all.c | 8 ++++---- 6 files changed, 26 insertions(+), 27 deletions(-) diff --git a/hw/arm/omap1.c b/hw/arm/omap1.c index 91ffb589e5..de2b289257 100644 --- a/hw/arm/omap1.c +++ b/hw/arm/omap1.c @@ -2004,8 +2004,7 @@ static void omap_mpuio_write(void *opaque, hwaddr addr, case 0x04: /* OUTPUT_REG */ diff = (s->outputs ^ value) & ~s->dir; s->outputs = value; - while ((ln = ffs(diff))) { - ln --; + while ((ln = ctz32(diff)) != 32) { if (s->handler[ln]) qemu_set_irq(s->handler[ln], (value >> ln) & 1); diff &= ~(1 << ln); @@ -2017,8 +2016,7 @@ static void omap_mpuio_write(void *opaque, hwaddr addr, s->dir = value; value = s->outputs & ~s->dir; - while ((ln = ffs(diff))) { - ln --; + while ((ln = ctz32(diff)) != 32) { if (s->handler[ln]) qemu_set_irq(s->handler[ln], (value >> ln) & 1); diff &= ~(1 << ln); diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index e336bdb4a9..6e2ad8221b 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -814,12 +814,12 @@ static uint32_t find_free_port_id(VirtIOSerial *vser) max_nr_ports = vser->serial.max_virtserial_ports; for (i = 0; i < (max_nr_ports + 31) / 32; i++) { - uint32_t map, bit; + uint32_t map, zeroes; map = vser->ports_map[i]; - bit = ffs(~map); - if (bit) { - return (bit - 1) + i * 32; + zeroes = ctz32(~map); + if (zeroes != 32) { + return zeroes + i * 32; } } return VIRTIO_CONSOLE_BAD_ID; diff --git a/hw/gpio/omap_gpio.c b/hw/gpio/omap_gpio.c index 9a43486890..d92f8cfbae 100644 --- a/hw/gpio/omap_gpio.c +++ b/hw/gpio/omap_gpio.c @@ -125,8 +125,7 @@ static void omap_gpio_write(void *opaque, hwaddr addr, case 0x04: /* DATA_OUTPUT */ diff = (s->outputs ^ value) & ~s->dir; s->outputs = value; - while ((ln = ffs(diff))) { - ln --; + while ((ln = ctz32(diff)) != 32) { if (s->handler[ln]) qemu_set_irq(s->handler[ln], (value >> ln) & 1); diff &= ~(1 << ln); @@ -138,8 +137,7 @@ static void omap_gpio_write(void *opaque, hwaddr addr, s->dir = value; value = s->outputs & ~s->dir; - while ((ln = ffs(diff))) { - ln --; + while ((ln = ctz32(diff)) != 32) { if (s->handler[ln]) qemu_set_irq(s->handler[ln], (value >> ln) & 1); diff &= ~(1 << ln); @@ -253,8 +251,7 @@ static inline void omap2_gpio_module_out_update(struct omap2_gpio_s *s, s->outputs ^= diff; diff &= ~s->dir; - while ((ln = ffs(diff))) { - ln --; + while ((ln = ctz32(diff)) != 32) { qemu_set_irq(s->handler[ln], (s->outputs >> ln) & 1); diff &= ~(1 << ln); } @@ -442,8 +439,8 @@ static void omap2_gpio_module_write(void *opaque, hwaddr addr, s->dir = value; value = s->outputs & ~s->dir; - while ((ln = ffs(diff))) { - diff &= ~(1 <<-- ln); + while ((ln = ctz32(diff)) != 32) { + diff &= ~(1 << ln); qemu_set_irq(s->handler[ln], (value >> ln) & 1); } diff --git a/hw/i2c/omap_i2c.c b/hw/i2c/omap_i2c.c index d63278dbde..b6f544a221 100644 --- a/hw/i2c/omap_i2c.c +++ b/hw/i2c/omap_i2c.c @@ -171,9 +171,13 @@ static uint32_t omap_i2c_read(void *opaque, hwaddr addr) case 0x0c: /* I2C_IV */ if (s->revision >= OMAP2_INTR_REV) break; - ret = ffs(s->stat & s->mask); - if (ret) - s->stat ^= 1 << (ret - 1); + ret = ctz32(s->stat & s->mask); + if (ret != 32) { + s->stat ^= 1 << ret; + ret++; + } else { + ret = 0; + } omap_i2c_interrupts_update(s); return ret; diff --git a/hw/intc/allwinner-a10-pic.c b/hw/intc/allwinner-a10-pic.c index de820b9723..eed7621f13 100644 --- a/hw/intc/allwinner-a10-pic.c +++ b/hw/intc/allwinner-a10-pic.c @@ -23,7 +23,7 @@ static void aw_a10_pic_update(AwA10PICState *s) { uint8_t i; - int irq = 0, fiq = 0, pending; + int irq = 0, fiq = 0, zeroes; s->vector = 0; @@ -32,9 +32,9 @@ static void aw_a10_pic_update(AwA10PICState *s) fiq |= s->select[i] & s->irq_pending[i] & ~s->mask[i]; if (!s->vector) { - pending = ffs(s->irq_pending[i] & ~s->mask[i]); - if (pending) { - s->vector = (i * 32 + pending - 1) * 4; + zeroes = ctz32(s->irq_pending[i] & ~s->mask[i]); + if (zeroes != 32) { + s->vector = (i * 32 + zeroes) * 4; } } } diff --git a/kvm-all.c b/kvm-all.c index 4ec153df93..2a717e5b50 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -1141,18 +1141,18 @@ static int kvm_irqchip_get_virq(KVMState *s) { uint32_t *word = s->used_gsi_bitmap; int max_words = ALIGN(s->gsi_count, 32) / 32; - int i, bit; + int i, zeroes; bool retry = true; again: /* Return the lowest unused GSI in the bitmap */ for (i = 0; i < max_words; i++) { - bit = ffs(~word[i]); - if (!bit) { + zeroes = ctz32(~word[i]); + if (zeroes == 32) { continue; } - return bit - 1 + i * 32; + return zeroes + i * 32; } if (!s->direct_msi && retry) { retry = false;