arch/m68k/math-emu/multi_arith.h

File Facts

System

Linux kernel

Corpus path

arch/m68k/math-emu/multi_arith.h

Extension

.h

Size

8911 bytes

Lines

291

Domain

Architecture Layer

Bucket

arch/m68k

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.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• fp_emu.h

Detected Declarations

• function fp_denormalize
• function fp_overnormalize
• function fp_addmant
• function fp_addcarry
• function fp_submant
• function fp_multiplymant
• function fp_dividemant
• function fp_putmant128

Annotated Snippet

if (src->mant.m32[0] == div->mant.m32[0]) {
			fp_div64(first, rem, 0, src->mant.m32[1], div->mant.m32[0]);

			fp_mul64(*mantp, dummy, first, fix);
			*mantp += fix;
		} else {
			fp_div64(first, rem, src->mant.m32[0], src->mant.m32[1], div->mant.m32[0]);

			fp_mul64(*mantp, dummy, first, fix);
		}

		fp_mul64(tmp.m32[0], tmp.m32[1], div->mant.m32[0], first - *mantp);
		fp_add64(tmp.m32[0], tmp.m32[1], 0, rem);
		tmp.m32[2] = 0;

		fp_mul64(tmp64.m32[0], tmp64.m32[1], *mantp, div->mant.m32[1]);
		fp_sub96c(tmp, 0, tmp64.m32[0], tmp64.m32[1]);

		src->mant.m32[0] = tmp.m32[1];
		src->mant.m32[1] = tmp.m32[2];

		while (!fp_sub96c(tmp, 0, div->mant.m32[0], div->mant.m32[1])) {
			src->mant.m32[0] = tmp.m32[1];
			src->mant.m32[1] = tmp.m32[2];
			*mantp += 1;
		}
	}
}

static inline void fp_putmant128(struct fp_ext *dest, union fp_mant128 *src,
				 int shift)
{
	unsigned long tmp;

	switch (shift) {
	case 0:
		dest->mant.m64 = src->m64[0];
		dest->lowmant = src->m32[2] >> 24;
		if (src->m32[3] || (src->m32[2] << 8))
			dest->lowmant |= 1;
		break;
	case 1:
		asm volatile ("lsl.l #1,%0"
			: "=d" (tmp) : "0" (src->m32[2]));
		asm volatile ("roxl.l #1,%0"
			: "=d" (dest->mant.m32[1]) : "0" (src->m32[1]));
		asm volatile ("roxl.l #1,%0"
			: "=d" (dest->mant.m32[0]) : "0" (src->m32[0]));
		dest->lowmant = tmp >> 24;
		if (src->m32[3] || (tmp << 8))
			dest->lowmant |= 1;
		break;
	case 31:
		asm volatile ("lsr.l #1,%1; roxr.l #1,%0"
			: "=d" (dest->mant.m32[0])
			: "d" (src->m32[0]), "0" (src->m32[1]));
		asm volatile ("roxr.l #1,%0"
			: "=d" (dest->mant.m32[1]) : "0" (src->m32[2]));
		asm volatile ("roxr.l #1,%0"
			: "=d" (tmp) : "0" (src->m32[3]));
		dest->lowmant = tmp >> 24;
		if (src->m32[3] << 7)
			dest->lowmant |= 1;
		break;
	case 32:
		dest->mant.m32[0] = src->m32[1];
		dest->mant.m32[1] = src->m32[2];
		dest->lowmant = src->m32[3] >> 24;
		if (src->m32[3] << 8)
			dest->lowmant |= 1;
		break;
	}
}

#endif	/* _MULTI_ARITH_H */

Annotation

• Immediate include surface: `fp_emu.h`.
• Detected declarations: `function fp_denormalize`, `function fp_overnormalize`, `function fp_addmant`, `function fp_addcarry`, `function fp_submant`, `function fp_multiplymant`, `function fp_dividemant`, `function fp_putmant128`.
• Atlas domain: Architecture Layer / arch/m68k.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.