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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 20:51:44 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 20:51:44 -0700 |
commit | bdfa54dfd9eea001274dbcd622657a904fe43b81 (patch) | |
tree | ab251ab359e519656d7061bbe8db4c7ab355404b /arch/s390/lib/div64.c | |
parent | 2481bc75283ea10e75d5fb1a8b42af363fc4b45c (diff) | |
parent | a1307bba1adcc9b338511180fa94a54b4c3f534b (diff) | |
download | linux-bdfa54dfd9eea001274dbcd622657a904fe43b81.tar.bz2 |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Martin Schwidefsky:
"The major change in this merge is the removal of the support for
31-bit kernels. Naturally 31-bit user space will continue to work via
the compat layer.
And then some cleanup, some improvements and bug fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (23 commits)
s390/smp: wait until secondaries are active & online
s390/hibernate: fix save and restore of kernel text section
s390/cacheinfo: add missing facility check
s390/syscalls: simplify syscall_get_arch()
s390/irq: enforce correct irqclass_sub_desc array size
s390: remove "64" suffix from mem64.S and swsusp_asm64.S
s390/ipl: cleanup macro usage
s390/ipl: cleanup shutdown_action attributes
s390/ipl: cleanup bin attr usage
s390/uprobes: fix address space annotation
s390: add missing arch_release_task_struct() declaration
s390: make couple of functions and variables static
s390/maccess: improve s390_kernel_write()
s390/maccess: remove potentially broken probe_kernel_write()
s390/watchdog: support for KVM hypervisors and delete pr_info messages
s390/watchdog: enable KEEPALIVE for /dev/watchdog
s390/dasd: remove setting of scheduler from driver
s390/traps: panic() instead of die() on translation exception
s390: remove test_facility(2) (== z/Architecture mode active) checks
s390/cmpxchg: simplify cmpxchg_double
...
Diffstat (limited to 'arch/s390/lib/div64.c')
-rw-r--r-- | arch/s390/lib/div64.c | 147 |
1 files changed, 0 insertions, 147 deletions
diff --git a/arch/s390/lib/div64.c b/arch/s390/lib/div64.c deleted file mode 100644 index 261152f83242..000000000000 --- a/arch/s390/lib/div64.c +++ /dev/null @@ -1,147 +0,0 @@ -/* - * __div64_32 implementation for 31 bit. - * - * Copyright IBM Corp. 2006 - * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), - */ - -#include <linux/types.h> -#include <linux/module.h> - -#ifdef CONFIG_MARCH_G5 - -/* - * Function to divide an unsigned 64 bit integer by an unsigned - * 31 bit integer using signed 64/32 bit division. - */ -static uint32_t __div64_31(uint64_t *n, uint32_t base) -{ - register uint32_t reg2 asm("2"); - register uint32_t reg3 asm("3"); - uint32_t *words = (uint32_t *) n; - uint32_t tmp; - - /* Special case base==1, remainder = 0, quotient = n */ - if (base == 1) - return 0; - /* - * Special case base==0 will cause a fixed point divide exception - * on the dr instruction and may not happen anyway. For the - * following calculation we can assume base > 1. The first - * signed 64 / 32 bit division with an upper half of 0 will - * give the correct upper half of the 64 bit quotient. - */ - reg2 = 0UL; - reg3 = words[0]; - asm volatile( - " dr %0,%2\n" - : "+d" (reg2), "+d" (reg3) : "d" (base) : "cc" ); - words[0] = reg3; - reg3 = words[1]; - /* - * To get the lower half of the 64 bit quotient and the 32 bit - * remainder we have to use a little trick. Since we only have - * a signed division the quotient can get too big. To avoid this - * the 64 bit dividend is halved, then the signed division will - * work. Afterwards the quotient and the remainder are doubled. - * If the last bit of the dividend has been one the remainder - * is increased by one then checked against the base. If the - * remainder has overflown subtract base and increase the - * quotient. Simple, no ? - */ - asm volatile( - " nr %2,%1\n" - " srdl %0,1\n" - " dr %0,%3\n" - " alr %0,%0\n" - " alr %1,%1\n" - " alr %0,%2\n" - " clr %0,%3\n" - " jl 0f\n" - " slr %0,%3\n" - " ahi %1,1\n" - "0:\n" - : "+d" (reg2), "+d" (reg3), "=d" (tmp) - : "d" (base), "2" (1UL) : "cc" ); - words[1] = reg3; - return reg2; -} - -/* - * Function to divide an unsigned 64 bit integer by an unsigned - * 32 bit integer using the unsigned 64/31 bit division. - */ -uint32_t __div64_32(uint64_t *n, uint32_t base) -{ - uint32_t r; - - /* - * If the most significant bit of base is set, divide n by - * (base/2). That allows to use 64/31 bit division and gives a - * good approximation of the result: n = (base/2)*q + r. The - * result needs to be corrected with two simple transformations. - * If base is already < 2^31-1 __div64_31 can be used directly. - */ - r = __div64_31(n, ((signed) base < 0) ? (base/2) : base); - if ((signed) base < 0) { - uint64_t q = *n; - /* - * First transformation: - * n = (base/2)*q + r - * = ((base/2)*2)*(q/2) + ((q&1) ? (base/2) : 0) + r - * Since r < (base/2), r + (base/2) < base. - * With q1 = (q/2) and r1 = r + ((q&1) ? (base/2) : 0) - * n = ((base/2)*2)*q1 + r1 with r1 < base. - */ - if (q & 1) - r += base/2; - q >>= 1; - /* - * Second transformation. ((base/2)*2) could have lost the - * last bit. - * n = ((base/2)*2)*q1 + r1 - * = base*q1 - ((base&1) ? q1 : 0) + r1 - */ - if (base & 1) { - int64_t rx = r - q; - /* - * base is >= 2^31. The worst case for the while - * loop is n=2^64-1 base=2^31+1. That gives a - * maximum for q=(2^64-1)/2^31 = 0x1ffffffff. Since - * base >= 2^31 the loop is finished after a maximum - * of three iterations. - */ - while (rx < 0) { - rx += base; - q--; - } - r = rx; - } - *n = q; - } - return r; -} - -#else /* MARCH_G5 */ - -uint32_t __div64_32(uint64_t *n, uint32_t base) -{ - register uint32_t reg2 asm("2"); - register uint32_t reg3 asm("3"); - uint32_t *words = (uint32_t *) n; - - reg2 = 0UL; - reg3 = words[0]; - asm volatile( - " dlr %0,%2\n" - : "+d" (reg2), "+d" (reg3) : "d" (base) : "cc" ); - words[0] = reg3; - reg3 = words[1]; - asm volatile( - " dlr %0,%2\n" - : "+d" (reg2), "+d" (reg3) : "d" (base) : "cc" ); - words[1] = reg3; - return reg2; -} - -#endif /* MARCH_G5 */ |