nx_zimage_flashattn_verify.nx source
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1// nx_zimage_flashattn_verify.nx -- SOVEREIGN FlashAttention (online-softmax) SDPA, verified EXACT vs oracle.
2//
3// The O(n)-memory attention: instead of building the n x n score matrix, softmaxing, then weighting V,
4// we STREAM keys into a running accumulator, rescaling it by exp(m_old - m_new) as the running max grows.
5// Peak memory is O(d) per query (the accumulator + 3 scalars m,l,a), NOT O(n) -- so it scales to any n
6// without materializing scores. This organ proves the recurrence is NUMERICALLY IDENTICAL to standard
7// softmax attention (verifies vs the same oracle ao_pre as the direct SDPA). Lossless, not an approximation.
8// Uses a LOCAL accumulator (no mmap scratch in the loop) per the nx_cc codegen lesson. No 3rd party.
9// license_tier: ORIGINAL
10import "nx_syscalls.nx"
11import "nx_le.nx"
12import "nx_f32.nx"
13import "nx_f32_div.nx"
14import "nx_f32_cvt.nx"
15import "nx_f32_exp.nx"
16import "nx_strconv.nx"
17const K_MAGIC_3840: i64 = 3840
18const K_MAGIC_11520: i64 = 11520
19
20func zfa_load(name: *u8, nl: i64, n_floats: i64) -> *u8 {
21 let base: *u8 = "/mnt/c/Users/elder/AppData/Local/Temp/claude/C--Users-elder/7be78b15-304c-449e-afe8-4d5bd7ddaa9c/scratchpad/zblk/" as *u8
22 let path: *u8 = sys_mmap(256)
23 var p: i64 = 0
24 var i: i64 = 0
25 while base[i] != 0 { path[p] = base[i]; p = p + 1; i = i + 1 }
26 i = 0
27 while i < nl { path[p] = name[i]; p = p + 1; i = i + 1 }
28 path[p] = 0x2E; p = p + 1
29 path[p] = 0x66; p = p + 1
30 path[p] = 0x33; p = p + 1
31 path[p] = 0x32; p = p + 1
32 path[p] = 0
33 let fd: i64 = sys_openat_rd(path)
34 if fd < 0 { return 0 as *u8 }
35 let bytes: i64 = n_floats * 4
36 let buf: *u8 = sys_mmap(bytes + 64)
37 var tot: i64 = 0
38 var go: i64 = 1
39 while go == 1 { let r: i64 = sys_read(fd, ((buf as i64) + tot) as *u8, bytes - tot); if r <= 0 { go = 0 } else { tot = tot + r; if tot >= bytes { go = 0 } } }
40 sys_close(fd)
41 return buf
42}
43
44func main() -> i64 {
45 let D: i64 = K_MAGIC_3840
46 let H: i64 = 30
47 let HD: i64 = 128
48 let NT: i64 = 4
49 let QKV: i64 = K_MAGIC_11520
50 let qr: *u8 = zfa_load("q_roped" as *u8, 7, NT * D)
51 let kr: *u8 = zfa_load("k_roped" as *u8, 7, NT * D)
52 let qkvd: *u8 = zfa_load("qkv" as *u8, 3, NT * QKV)
53 let aog: *u8 = zfa_load("ao_pre" as *u8, 6, NT * D)
54 if (qr as i64) == 0 { return 30 }
55 if (kr as i64) == 0 { return 32 }
56 if (qkvd as i64) == 0 { return 33 }
57 if (aog as i64) == 0 { return 31 }
58
59 let scale: i64 = nx_f32_div(nx_i32_to_f32(1), nx_f32_sqrt(nx_i32_to_f32(128)))
60 let tolc: i64 = nx_f32_div(nx_i32_to_f32(3), nx_i32_to_f32(100))
61 let one: i64 = nx_i32_to_f32(1)
62 let vbase: i64 = D + D
63 var fails: i64 = 0
64 var first_bad: i64 = 0 - 1
65
66 var hd: i64 = 0
67 while hd < H {
68 var t1: i64 = 0
69 while t1 < NT {
70 // --- scores q.k for the 4 keys (one d-loop) ---
71 let qb: i64 = (t1 * D + hd * HD) * 4
72 let k0b: i64 = (hd * HD) * 4
73 let k1b: i64 = (D + hd * HD) * 4
74 let k2b: i64 = (2 * D + hd * HD) * 4
75 let k3b: i64 = (3 * D + hd * HD) * 4
76 var s0: i64 = 0
77 var s1: i64 = 0
78 var s2: i64 = 0
79 var s3: i64 = 0
80 var d: i64 = 0
81 while d < HD {
82 let qd: i64 = nx_le_read_u32(qr, qb + d * 4)
83 s0 = nx_f32_add(s0, nx_f32_mul(qd, nx_le_read_u32(kr, k0b + d * 4)))
84 s1 = nx_f32_add(s1, nx_f32_mul(qd, nx_le_read_u32(kr, k1b + d * 4)))
85 s2 = nx_f32_add(s2, nx_f32_mul(qd, nx_le_read_u32(kr, k2b + d * 4)))
86 s3 = nx_f32_add(s3, nx_f32_mul(qd, nx_le_read_u32(kr, k3b + d * 4)))
87 d = d + 1
88 }
89 s0 = nx_f32_mul(s0, scale)
90 s1 = nx_f32_mul(s1, scale)
91 s2 = nx_f32_mul(s2, scale)
92 s3 = nx_f32_mul(s3, scale)
93
94 // --- ONLINE SOFTMAX: streaming rescale scalars (never store all scores) ---
95 // key0: m=s0, l=1, acc=v0
96 var m: i64 = s0
97 // key1
98 var mn: i64 = m
99 if nx_f32_lt(mn, s1) == 1 { mn = s1 }
100 let corr0: i64 = nx_f32_exp(nx_f32_sub(m, mn))
101 let p1: i64 = nx_f32_exp(nx_f32_sub(s1, mn))
102 m = mn
103 // key2
104 mn = m
105 if nx_f32_lt(mn, s2) == 1 { mn = s2 }
106 let corr1: i64 = nx_f32_exp(nx_f32_sub(m, mn))
107 let p2: i64 = nx_f32_exp(nx_f32_sub(s2, mn))
108 m = mn
109 // key3
110 mn = m
111 if nx_f32_lt(mn, s3) == 1 { mn = s3 }
112 let corr2: i64 = nx_f32_exp(nx_f32_sub(m, mn))
113 let p3: i64 = nx_f32_exp(nx_f32_sub(s3, mn))
114 m = mn
115 // running normalizer l (same recurrence)
116 var l: i64 = one
117 l = nx_f32_add(nx_f32_mul(l, corr0), p1)
118 l = nx_f32_add(nx_f32_mul(l, corr1), p2)
119 l = nx_f32_add(nx_f32_mul(l, corr2), p3)
120
121 let v0b: i64 = (vbase + hd * HD) * 4
122 let v1b: i64 = (QKV + vbase + hd * HD) * 4
123 let v2b: i64 = (2 * QKV + vbase + hd * HD) * 4
124 let v3b: i64 = (3 * QKV + vbase + hd * HD) * 4
125
126 // --- per-channel online accumulate with a LOCAL (no scratch array) ---
127 var d2: i64 = 0
128 while d2 < HD {
129 var a: i64 = nx_le_read_u32(qkvd, v0b + d2 * 4) // acc_0 = v0
130 a = nx_f32_add(nx_f32_mul(a, corr0), nx_f32_mul(p1, nx_le_read_u32(qkvd, v1b + d2 * 4))) // key1
131 a = nx_f32_add(nx_f32_mul(a, corr1), nx_f32_mul(p2, nx_le_read_u32(qkvd, v2b + d2 * 4))) // key2
132 a = nx_f32_add(nx_f32_mul(a, corr2), nx_f32_mul(p3, nx_le_read_u32(qkvd, v3b + d2 * 4))) // key3
133 a = nx_f32_div(a, l)
134 let g: i64 = nx_le_read_u32(aog, (t1 * D + hd * HD + d2) * 4)
135 var thr: i64 = tolc
136 let ag: i64 = g & 0x7FFFFFFF
137 if nx_f32_lt(thr, nx_f32_mul(tolc, ag)) == 1 { thr = nx_f32_mul(tolc, ag) }
138 if (nx_f32_sub(a, g) & 0x7FFFFFFF) >= thr { fails = fails + 1; if first_bad < 0 { first_bad = t1 * D + hd * HD + d2 } }
139 d2 = d2 + 1
140 }
141 t1 = t1 + 1
142 }
143 hd = hd + 1
144 }
145
146 let ofd: i64 = sys_openat_wr("/tmp/zfa.txt" as *u8, 0x1a4)
147 if ofd >= 0 {
148 let dec: *u8 = sys_mmap(32)
149 sys_write(ofd, "fails=" as *u8, 6); let n1: i64 = nx_strconv_format_i64(fails, dec); sys_write(ofd, dec, n1)
150 sys_write(ofd, " first_bad=" as *u8, 11); let n2: i64 = nx_strconv_format_i64(first_bad, dec); sys_write(ofd, dec, n2)
151 sys_write(ofd, "\n" as *u8, 1); sys_close(ofd)
152 }
153 if fails > 0 { return 20 }
154 return 0
155}