arch/powerpc/math-emu/mcrfs.c

Source file repositories/reference/linux-study-clean/arch/powerpc/math-emu/mcrfs.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/math-emu/mcrfs.c
Extension
.c
Size
620 bytes
Lines
34
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

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

// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/uaccess.h>

#include <asm/sfp-machine.h>
#include <math-emu/soft-fp.h>

int
mcrfs(u32 *ccr, u32 crfD, u32 crfS)
{
	u32 value, clear;

#ifdef DEBUG
	printk("%s: %p (%08x) %d %d\n", __func__, ccr, *ccr, crfD, crfS);
#endif

	clear = 15 << ((7 - crfS) << 2);
	if (!crfS)
		clear = 0x90000000;

	value = (__FPU_FPSCR >> ((7 - crfS) << 2)) & 15;
	__FPU_FPSCR &= ~(clear);

	*ccr &= ~(15 << ((7 - crfD) << 2));
	*ccr |= (value << ((7 - crfD) << 2));

#ifdef DEBUG
	printk("CR: %08x\n", __func__, *ccr);
#endif

	return 0;
}

Annotation

Implementation Notes