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notes.txt
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notes.txt
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AVL
00000 0
00001 1
00010 2
00011 3
00100 4
00101 5
00110 6
00111 7
01000 8
01001 9
01010 10
01011 11
01100 12
01101 13
01110 14
01111 15
10000 16 uimm[4:3] << uimm[2:0]
10001 32
10010 64
10011 128
10100 256
10101 512
10110 1024
10111 2048
11000 24
11001 48
11010 96
11011 192
11100 384
11101 768
11110 1536
11111 3072
if (uimm[4])
AVL = uimm[4:3] << (uimm[2:0] + 3)
else
AVL = uimm[3:0]
SLEN=VLEN=32b
Byte 3 2 1 0
LMUL=1,SEW=8b
3 2 1 0 Element
[3] [2] [1] [0] Mask bit position in decimal
LMUL=2,SEW=16b
1 0
[01] [00]
3 2
[03] [02]
LMUL=4,SEW=32b 0
[00]
1
[01]
2
[02]
3
[03]
----
----
LMUL=2,SEW=8b
3 2 1 0
[12][08][04][00]
7 6 5 4
[28][24][20][16]
LMUL=8,SEW=32b
0
[00]
1
[04]
2
[08]
3
[12]
4
[16]
5
[20]
6
[24]
7
[28]
LMUL=8,SEW=8b
3 2 1 0
[03][02][01][00]
7 6 5 4
[07][06][05][04]
B A 9 8
[11][10][09][08]
F E D C
[15][14][13][12]
13 12 11 10
[19][18][17][16]
17 16 15 14
[23][22][21][20]
1B 1A 19 18
[27][26][25][24]
1F 1E 1D 1C
[31][30][29][28]
----
When LMUL < 1, the mask elements are accessed as if LMUL=1 and the
vector length was reduced.
=== Mask Element Locations for SLEN < VLEN
In systems with SLEN < VLEN, the mask elements are striped across the
VLEN/SLEN sections of the vector mask register. Mask element 0 is in
least-significant bits of section 0, and mask element 1 is in
least-significant bits of section 1, etc. In general, the
least-significant bit of the mask element for element __i__ is located
at bit:
mask_LSB_index(__i__) = (__i__ % (VLEN / SLEN)) * SLEN + floor(__i__ / (VLEN / SLEN)) * MLEN
----
Mask register element location examples for SLEN < VLEN
The bit position of the LSB of each mask element is in decimal inside [] braces.
VLEN=256b, SLEN=128b, SEW=32b, LMUL=2, MLEN=16b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2*n 7 5 3 1| 6 4 2 0
[7] [5] [3] [1] [6] [4] [2] [0]
v2*n+1 F D B 9| E C A 8
[240] [224] [208] [192] [112] [96] [80] [64]
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2*n 7 5 3 1| 6 4 2 0
[131] [130] [129] [128] [3] [2] [1] [0]
v2*n+1 F D B 9| E C A 8
[135] [134] [133] [132] [7] [6] [5] [4]
SEW=8b, LMUL=1/2
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2*n - - - - - - - - F D B 9 7 5 3 1| - - - - - - - - E C A B 6 4 2 0
[135].........[128] [7[6[5[4[3[2[1[0]
v2*n+1 F D B 9| E C A 8
[135] [134] [133] [132] [7] [6] [5] [4]
VLEN=256b, SLEN=128b, SEW=64b, LMUL=1, MLEN=64b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
vn 3 1| 2 0
[129] [128] [1] [0]
VLEN=256b, SLEN=128b, SEW=32b, LMUL=1/2, MLEN=64b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
vn - - 3 1| - - 2 0
[129] [128] [1] [0]
VLEN=256b, SLEN=128b, SEW=64b, LMUL=1, MLEN=64b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
vn 3 1| 2 0
[192] [128] [64] [0]
----
----------------------------------------------------------------------
VLEN=256b, SLEN=128b, SEW=32b, LMUL=2
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2*n 7 5 3 1| 6 4 2 0
v2*n+1 F D B 9| E C A 8
VLEN=512b, SLEN=128b, SEW=32b, LMUL=1
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 D 9 5 1| C 8 4 0
3 2
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 F B 7 3| E A 6 2
VLEN=512b, SLEN=128b, SEW=64b, LMUL=1
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 [A,B] 5 [2,3] 1| [8,9] 4 [0,1] 0
3 2
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 [E,F] 7 [6,7] 3| [C,D] 6 [4,5] 2
----------------------------------------------------------------------
fix SLEN=128b, DLEN>=128
VLEN=512b, SLEN=128, DLEN=256, EEW=16b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 7 5 3 1| 6 4 2 0
v2 F D B 9| E C A 8
VLEN=512b, SLEN=128, DLEN=256, EEW=32b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 7 5 3 1| 6 4 2 0
v2 F D B 9| E C A 8
VLEN=512b, SLEN=128, DLEN=256, EEW=64b
Section 1 | 0
Byte 1F1E1D1C1B1A19181716151413121110| F E D C B A 9 8 7 6 5 4 3 2 1 0
v2 3 1| 2 0
v2 7 5| 6 4