arch/m68k/fpsp040/satanh.S

Source file repositories/reference/linux-study-clean/arch/m68k/fpsp040/satanh.S

File Facts

System
Linux kernel
Corpus path
arch/m68k/fpsp040/satanh.S
Extension
.S
Size
2235 bytes
Lines
104
Domain
Architecture Layer
Bucket
arch/m68k
Inferred role
Architecture Layer: arch/m68k
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

|
|	satanh.sa 3.3 12/19/90
|
|	The entry point satanh computes the inverse
|	hyperbolic tangent of
|	an input argument; satanhd does the same except for denormalized
|	input.
|
|	Input: Double-extended number X in location pointed to
|		by address register a0.
|
|	Output: The value arctanh(X) returned in floating-point register Fp0.
|
|	Accuracy and Monotonicity: The returned result is within 3 ulps in
|		64 significant bit, i.e. within 0.5001 ulp to 53 bits if the
|		result is subsequently rounded to double precision. The
|		result is provably monotonic in double precision.
|
|	Speed: The program satanh takes approximately 270 cycles.
|
|	Algorithm:
|
|	ATANH
|	1. If |X| >= 1, go to 3.
|
|	2. (|X| < 1) Calculate atanh(X) by
|		sgn := sign(X)
|		y := |X|
|		z := 2y/(1-y)
|		atanh(X) := sgn * (1/2) * logp1(z)
|		Exit.
|
|	3. If |X| > 1, go to 5.
|
|	4. (|X| = 1) Generate infinity with an appropriate sign and
|		divide-by-zero by
|		sgn := sign(X)
|		atan(X) := sgn / (+0).
|		Exit.
|
|	5. (|X| > 1) Generate an invalid operation by 0 * infinity.
|		Exit.
|

|		Copyright (C) Motorola, Inc. 1990
|			All Rights Reserved
|
|       For details on the license for this file, please see the
|       file, README, in this same directory.

|satanh	idnt	2,1 | Motorola 040 Floating Point Software Package

	|section	8

	|xref	t_dz
	|xref	t_operr
	|xref	t_frcinx
	|xref	t_extdnrm
	|xref	slognp1

	.global	satanhd
satanhd:
|--ATANH(X) = X FOR DENORMALIZED X

	bra		t_extdnrm

	.global	satanh
satanh:
	movel		(%a0),%d0
	movew		4(%a0),%d0

Annotation

Implementation Notes