arch/mips/math-emu/dp_tint.c

Source file repositories/reference/linux-study-clean/arch/mips/math-emu/dp_tint.c

File Facts

System
Linux kernel
Corpus path
arch/mips/math-emu/dp_tint.c
Extension
.c
Size
1980 bytes
Lines
97
Domain
Architecture Layer
Bucket
arch/mips
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

if (xe < -1) {
			residue = xm;
			round = 0;
			sticky = residue != 0;
			xm = 0;
		} else {
			residue = xm << (64 - DP_FBITS + xe);
			round = (residue >> 63) != 0;
			sticky = (residue << 1) != 0;
			xm >>= DP_FBITS - xe;
		}
		/* Note: At this point upper 32 bits of xm are guaranteed
		   to be zero */
		odd = (xm & 0x1) != 0x0;
		switch (ieee754_csr.rm) {
		case FPU_CSR_RN:
			if (round && (sticky || odd))
				xm++;
			break;
		case FPU_CSR_RZ:
			break;
		case FPU_CSR_RU:	/* toward +Infinity */
			if ((round || sticky) && !xs)
				xm++;
			break;
		case FPU_CSR_RD:	/* toward -Infinity */
			if ((round || sticky) && xs)
				xm++;
			break;
		}
		/* look for valid corner case 0x80000000 */
		if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
			/* This can happen after rounding */
			ieee754_setcx(IEEE754_INVALID_OPERATION);
			return ieee754si_overflow(xs);
		}
		if (round || sticky)
			ieee754_setcx(IEEE754_INEXACT);
	}
	if (xs)
		return -xm;
	else
		return xm;
}

Annotation

Implementation Notes