drivers/gpu/drm/nouveau/nvkm/subdev/pmu/fuc/arith.fuc

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/fuc/arith.fuc

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/nouveau/nvkm/subdev/pmu/fuc/arith.fuc
Extension
.fuc
Size
2631 bytes
Lines
95
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: drivers/gpu
Status
atlas-only

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifdef INCLUDE_PROC
#endif

#ifdef INCLUDE_DATA
#endif

/******************************************************************************
 * arith code segment
 *****************************************************************************/
#ifdef INCLUDE_CODE

// does a 32x32 -> 64 multiplication
//
// A * B = A_lo * B_lo
//        + ( A_hi * B_lo ) << 16
//        + ( A_lo * B_hi ) << 16
//        + ( A_hi * B_hi ) << 32
//
// $r15 - current
// $r14 - A
// $r13 - B
// $r12 - mul_lo (return)
// $r11 - mul_hi (return)
// $r0  - zero
mulu32_32_64:
	push $r1 // A_hi
	push $r2 // B_hi
	push $r3 // tmp0
	push $r4 // tmp1

	shr b32 $r1 $r14 16
	shr b32 $r2 $r13 16

	clear b32 $r12
	clear b32 $r11

	// A_lo * B_lo
	mulu $r12 $r14 $r13

	// ( A_hi * B_lo ) << 16
	mulu $r3 $r1 $r13 // tmp0 = A_hi * B_lo
	mov b32 $r4 $r3
	and $r3 0xffff // tmp0 = tmp0_lo
	shl b32 $r3 16
	shr b32 $r4 16 // tmp1 = tmp0_hi
	add b32 $r12 $r3
	adc b32 $r11 $r4

	// ( A_lo * B_hi ) << 16
	mulu $r3 $r14 $r2 // tmp0 = A_lo * B_hi
	mov b32 $r4 $r3
	and $r3 0xffff // tmp0 = tmp0_lo
	shl b32 $r3 16
	shr b32 $r4 16 // tmp1 = tmp0_hi
	add b32 $r12 $r3
	adc b32 $r11 $r4

	// ( A_hi * B_hi ) << 32
	mulu $r3 $r1 $r2 // tmp0 = A_hi * B_hi
	add b32 $r11 $r3

	pop $r4
	pop $r3
	pop $r2
	pop $r1
	ret
#endif

Annotation

Implementation Notes