1//go:build !noasm && gc && amd64
 2// +build !noasm,gc,amd64
 3
 4package sha1cd
 5
 6import (
 7	"math"
 8	"unsafe"
 9
10	shared "github.com/pjbgf/sha1cd/internal"
11)
12
13type sliceHeader struct {
14	base uintptr
15	len  int
16	cap  int
17}
18
19// blockAMD64 hashes the message p into the current state in dig.
20// Both m1 and cs are used to store intermediate results which are used by the collision detection logic.
21//
22//go:noescape
23func blockAMD64(dig *digest, p sliceHeader, m1 []uint32, cs [][5]uint32)
24
25func block(dig *digest, p []byte) {
26	m1 := [shared.Rounds]uint32{}
27	cs := [shared.PreStepState][shared.WordBuffers]uint32{}
28
29	for len(p) >= shared.Chunk {
30		// Only send a block to be processed, as the collission detection
31		// works on a block by block basis.
32		ips := sliceHeader{
33			base: uintptr(unsafe.Pointer(&p[0])),
34			len:  int(math.Min(float64(len(p)), float64(shared.Chunk))),
35			cap:  shared.Chunk,
36		}
37
38		blockAMD64(dig, ips, m1[:], cs[:])
39
40		col := checkCollision(m1, cs, dig.h)
41		if col {
42			dig.col = true
43
44			blockAMD64(dig, ips, m1[:], cs[:])
45			blockAMD64(dig, ips, m1[:], cs[:])
46		}
47
48		p = p[shared.Chunk:]
49	}
50}