3 void daxpy(size_t n, double a, const double x[], double y[])
5 for (size_t i = 0; i < n; i++) {
11 # SVP64 Power ISA version
16 mtctr 5 # move n to CTR
17 addi r10,r6,0 # copy y-ptr into r10
19 setvl MAXVL=32,VL=CTR # could do more
20 sv.lfdup/els *32,8(6) # load from x
21 sv.lfdup/els *64,8(7) # load from y
22 sv.fmadd *64,*64,1,*32 # fmadd
23 stfdup/els *64,8(10) # store y-copy
24 sv.bc/ctr .L2 # decrement VL by CTR
28 # a0 is n, a1 is ptr to x[0], a2 is ptr to y[0], fa0 is a (scalar)
29 VBLK.REG[0] = {type: F, isvec: 1, regkey: a3, regidx: a3, elwidth: dflt}
30 VBLK.REG[1] = {type: F, isvec: 1, regkey: a7, regidx: a7, elwidth: dflt}
32 VBLK.SETVL t0, a0, #4 # MVL=4, vl = t0 = min(a0, MVL))
33 c.ld a3, a1 # load 4 registers a3-6 from x
34 c.slli t1, t0, 3 # t1 = vl * 8 (in bytes: FP is double)
35 c.ld a7, a2 # load 4 registers a7-10 from y
36 c.add a1, a1, t1 # increment pointer to x by vl*8
37 fmadd a7, a3, fa0, a7 # v1 += v0 * fa0 (y = a * x + y)
38 c.sub a0, a0, t0 # n -= vl (t0)
39 c.st a7, a2 # store 4 registers a7-10 to y
40 c.add a2, a2, t1 # increment pointer to y by vl*8
41 c.bnez a0, loop # repeat if n != 0
45 # a0 is n, a1 is pointer to x[0], a2 is pointer to y[0], fa0 is a
47 vsetdcfg t0 # enable 2 64b Fl.Pt. registers
49 setvl t0, a0 # vl = t0 = min(mvl, n)
50 vld v0, a1 # load vector x
51 c.slli t1, t0, 3 # t1 = vl * 8 (in bytes)
52 vld v1, a2 # load vector y
53 c.add a1, a1, t1 # increment pointer to x by vl*8
54 vfmadd v1, v0, fa0, v1 # v1 += v0 * fa0 (y = a * x + y)
55 c.sub a0, a0, t0 # n -= vl (t0)
57 c.add a2, a2, t1 # increment pointer to y by vl*8
58 c.bnez a0, loop # repeat if n != 0