diff options
author | Olof Johansson <olof@lixom.net> | 2012-02-10 12:40:34 -0800 |
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committer | Olof Johansson <olof@lixom.net> | 2012-02-10 12:40:34 -0800 |
commit | 082f53c2f573c75a8f1610c587a43b6817e20f90 (patch) | |
tree | c3ad3a58967e7f7f61ff12ff59284dba1e76d093 /drivers/gpu/drm/radeon/r600_blit_kms.c | |
parent | e69128b947da0a2474447868f73c76311e2baedb (diff) | |
parent | b024e33682c8e56cc8e869245dabd1b91ffe00ea (diff) |
Merge branch 'for-arm-soc' of git://sources.calxeda.com/kernel/linux into next/soc
* 'for-arm-soc' of git://sources.calxeda.com/kernel/linux: (247 commits)
ARM: highbank: remove unused memory.h
ARM: highbank: enable sp804 based sched_clock
ARM: timer-sp: add sched_clock support
Linux 3.3-rc3
pcmcia: fix socket refcount decrementing on each resume
mm: fix UP THP spin_is_locked BUGs
drivers/leds/leds-lm3530.c: fix setting pltfm->als_vmax
mm: compaction: check for overlapping nodes during isolation for migration
nilfs2: avoid overflowing segment numbers in nilfs_ioctl_clean_segments()
ASoC: wm8994: Disable line output discharge prior to ramping VMID
ASoC: wm8994: Fix typo in VMID ramp setting
ALSA: oxygen, virtuoso: fix exchanged L/R volumes of aux and CD inputs
ALSA: usb-audio: add Edirol UM-3G support
checkpatch: Warn on code with 6+ tab indentation
ACPI: remove duplicated lines of merging problems with acpi_processor_add
ALSA: hda - add support for Uniwill ECS M31EI notebook
HID: wiimote: fix invalid power_supply_powers call
ALSA: hda - Fix error handling in patch_ca0132.c
target: Fix unsupported WRITE_SAME sense payload
iscsi: use IP_FREEBIND socket option
...
Diffstat (limited to 'drivers/gpu/drm/radeon/r600_blit_kms.c')
-rw-r--r-- | drivers/gpu/drm/radeon/r600_blit_kms.c | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/drivers/gpu/drm/radeon/r600_blit_kms.c b/drivers/gpu/drm/radeon/r600_blit_kms.c index d996f438113..accc032c103 100644 --- a/drivers/gpu/drm/radeon/r600_blit_kms.c +++ b/drivers/gpu/drm/radeon/r600_blit_kms.c @@ -468,27 +468,42 @@ set_default_state(struct radeon_device *rdev) radeon_ring_write(ring, sq_stack_resource_mgmt_2); } +#define I2F_MAX_BITS 15 +#define I2F_MAX_INPUT ((1 << I2F_MAX_BITS) - 1) +#define I2F_SHIFT (24 - I2F_MAX_BITS) + +/* + * Converts unsigned integer into 32-bit IEEE floating point representation. + * Conversion is not universal and only works for the range from 0 + * to 2^I2F_MAX_BITS-1. Currently we only use it with inputs between + * 0 and 16384 (inclusive), so I2F_MAX_BITS=15 is enough. If necessary, + * I2F_MAX_BITS can be increased, but that will add to the loop iterations + * and slow us down. Conversion is done by shifting the input and counting + * down until the first 1 reaches bit position 23. The resulting counter + * and the shifted input are, respectively, the exponent and the fraction. + * The sign is always zero. + */ static uint32_t i2f(uint32_t input) { u32 result, i, exponent, fraction; - if ((input & 0x3fff) == 0) - result = 0; /* 0 is a special case */ + WARN_ON_ONCE(input > I2F_MAX_INPUT); + + if ((input & I2F_MAX_INPUT) == 0) + result = 0; else { - exponent = 140; /* exponent biased by 127; */ - fraction = (input & 0x3fff) << 10; /* cheat and only - handle numbers below 2^^15 */ - for (i = 0; i < 14; i++) { + exponent = 126 + I2F_MAX_BITS; + fraction = (input & I2F_MAX_INPUT) << I2F_SHIFT; + + for (i = 0; i < I2F_MAX_BITS; i++) { if (fraction & 0x800000) break; else { - fraction = fraction << 1; /* keep - shifting left until top bit = 1 */ + fraction = fraction << 1; exponent = exponent - 1; } } - result = exponent << 23 | (fraction & 0x7fffff); /* mask - off top bit; assumed 1 */ + result = exponent << 23 | (fraction & 0x7fffff); } return result; } |