diff options
Diffstat (limited to 'arch/xtensa/lib/divsi3.S')
| -rw-r--r-- | arch/xtensa/lib/divsi3.S | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/xtensa/lib/divsi3.S b/arch/xtensa/lib/divsi3.S new file mode 100644 index 0000000000..edb3c4ad97 --- /dev/null +++ b/arch/xtensa/lib/divsi3.S @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0 */ +#include <linux/linkage.h> +#include <asm/asmmacro.h> +#include <asm/core.h> + +ENTRY(__divsi3) + + abi_entry_default +#if XCHAL_HAVE_DIV32 + quos a2, a2, a3 +#else + xor a7, a2, a3 /* sign = dividend ^ divisor */ + do_abs a6, a2, a4 /* udividend = abs (dividend) */ + do_abs a3, a3, a4 /* udivisor = abs (divisor) */ + bltui a3, 2, .Lle_one /* check if udivisor <= 1 */ + do_nsau a5, a6, a2, a8 /* udividend_shift = nsau (udividend) */ + do_nsau a4, a3, a2, a8 /* udivisor_shift = nsau (udivisor) */ + bgeu a5, a4, .Lspecial + + sub a4, a4, a5 /* count = udivisor_shift - udividend_shift */ + ssl a4 + sll a3, a3 /* udivisor <<= count */ + movi a2, 0 /* quotient = 0 */ + + /* test-subtract-and-shift loop; one quotient bit on each iteration */ +#if XCHAL_HAVE_LOOPS + loopnez a4, .Lloopend +#endif /* XCHAL_HAVE_LOOPS */ +.Lloop: + bltu a6, a3, .Lzerobit + sub a6, a6, a3 + addi a2, a2, 1 +.Lzerobit: + slli a2, a2, 1 + srli a3, a3, 1 +#if !XCHAL_HAVE_LOOPS + addi a4, a4, -1 + bnez a4, .Lloop +#endif /* !XCHAL_HAVE_LOOPS */ +.Lloopend: + + bltu a6, a3, .Lreturn + addi a2, a2, 1 /* increment if udividend >= udivisor */ +.Lreturn: + neg a5, a2 + movltz a2, a5, a7 /* return (sign < 0) ? -quotient : quotient */ + abi_ret_default + +.Lle_one: + beqz a3, .Lerror + neg a2, a6 /* if udivisor == 1, then return... */ + movgez a2, a6, a7 /* (sign < 0) ? -udividend : udividend */ + abi_ret_default + +.Lspecial: + bltu a6, a3, .Lreturn0 /* if dividend < divisor, return 0 */ + movi a2, 1 + movi a4, -1 + movltz a2, a4, a7 /* else return (sign < 0) ? -1 : 1 */ + abi_ret_default + +.Lerror: + /* Divide by zero: Use an illegal instruction to force an exception. + The subsequent "DIV0" string can be recognized by the exception + handler to identify the real cause of the exception. */ + ill + .ascii "DIV0" + +.Lreturn0: + movi a2, 0 +#endif /* XCHAL_HAVE_DIV32 */ + abi_ret_default + +ENDPROC(__divsi3) +EXPORT_SYMBOL(__divsi3) |