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请问其中ASIZE为什么是4?我觉得应该是3.我在一本书上看到也是4.7 B6 B/ K7 |' e
module fifo1(rdata, wfull, rempty, wdata, winc, wclk, wrst_n,rinc, rclk, rrst_n); 1 M! ^0 A, v* u5 y0 z4 R
parameter DSIZE = 8; parameter ASIZE = 4;
" W8 A; c' Y2 N! {6 n0 ^5 @( V5 p9 Eoutput [DSIZE-1:0] rdata; , x' G- J6 o% r2 g% ^9 ]. c
output wfull; 3 o) |- {5 B. z! o% }' P
output rempty;
, [, S1 t6 `# ?9 tinput [DSIZE-1:0] wdata; * V7 _% [6 O2 ~3 w9 u5 ?
input winc, wclk, wrst_n; ; k& V% j4 a' I; e7 F' {1 D
input rinc, rclk, rrst_n; 4 q6 ~. ? P1 G3 |0 P
reg wfull,rempty; ; b# \: o8 [2 S e& l M
reg [ASIZE:0] wptr, rptr, wq2_rptr, rq2_wptr, wq1_rptr,rq1_wptr;
% L/ A5 \; f2 kreg [ASIZE:0] rbin, wbin; 8 P; W; l" ~: s2 u+ F; Q" U
reg [DSIZE-1:0] mem[0: (1<<ASIZE)-1]; $ x- U* ~ K! X" O( A; s
wire [ASIZE-1:0] waddr, raddr;
g# n$ J8 w4 T, U9 g7 Q. ~. o5 ^, bwire [ASIZE:0] rgraynext, rbinnext,wgraynext,wbinnext; , [7 C! s6 p8 f/ m" g4 J
wire rempty_val,wfull_val; , K/ z% s! x }( _ U7 o$ o, k
8 g! J- q) w0 s' G& u6 [) Wassign rdata=mem[raddr]; % j0 U# g5 \: V* |3 M2 s6 k% ^' Y
always@(posedge wclk)
6 }1 S Q' x0 T* N; V, V6 sif (winc && !wfull) mem[waddr] <= wdata; 2 A7 e: f/ x, E4 Z# ?) X, R5 w
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always @(posedge wclk or negedge wrst_n)
( V7 P7 @0 w7 Fif (!wrst_n) {wq2_rptr,wq1_rptr} <= 0;
7 `4 B B' \, j$ V$ qelse {wq2_rptr,wq1_rptr} <= {wq1_rptr,rptr}; c! s& j9 {% j. h9 i$ B4 `
& c; T7 k3 x% F; calways @(posedge rclk or negedge rrst_n)
+ j/ g0 \# H5 Iif (!rrst_n) {rq2_wptr,rq1_wptr} <= 0; / ^% `/ X0 w) T3 W
else {rq2_wptr,rq1_wptr} <= {rq1_wptr,wptr};
. _& X$ {$ g( `4 l$ ]1 O4 E% y3 U2 M6 i$ p0 r7 G+ ?
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always @(posedge rclk or negedge rrst_n) // GRAYSTYLE2 pointer . J( B( t$ y B" L4 p `1 b
begin $ U+ ^7 S) v. ?5 F
if (!rrst_n) {rbin, rptr} <= 0; ) C& U2 w$ b9 q f; d+ J$ Q
else {rbin, rptr} <= {rbinnext, rgraynext};
/ a1 S( I2 j+ { C, V: yend
- _- F( k* \) B m: _: y& p) ]
$ {' n% C; ]! Y- ~& z/ F& o: d5 k& r- X
assign raddr = rbin[ASIZE-1:0]; " l' s# v/ \# ?( z$ k9 G
assign rbinnext = rbin + (rinc & ~rempty);
' U7 }: i6 r+ @8 G" Wassign rgraynext = (rbinnext>>1) ^ rbinnext; - E3 F6 A3 u/ w7 S# R
+ v& ?* q% \3 H* W$ H' P3 V& O/ i& I. w, ]( Q
assign rempty_val = (rgraynext == rq2_wptr); 0 M4 _" M% a/ p, o( l, a" m! S
always @(posedge rclk or negedge rrst_n)
( F6 w b' @% pbegin
) {% h; x5 E* ]) S+ |6 X. o; Qif (!rrst_n) rempty <= 1'b1; / E9 p& Y5 g1 O: R
else rempty <= rempty_val;
& W( y# [" M6 @3 ~* X* D- O$ fend $ f3 |+ n P, `0 Y& \. I6 F- ?
8 t2 A# b$ y ` W( I/ f: |& P! p2 c* ^& I
always @(posedge wclk or negedge wrst_n) // GRAYSTYLE2 pointer : {' J' h. |6 q
if (!wrst_n) {wbin, wptr} <= 0;
5 i6 p) `, L8 T; @. U; o1 [! s" yelse {wbin, wptr} <= {wbinnext, wgraynext};
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assign waddr = wbin[ASIZE-1:0];
4 J5 u+ g2 g i% T; T ?. sassign wbinnext = wbin + (winc & ~wfull);
. F% u& Q; W F; `assign wgraynext = (wbinnext>>1) ^ wbinnext; 3 P6 Q" w3 V; f- E4 `
assign wfull_val = (wgraynext=={~wq2_rptr[ASIZE:ASIZE-1], wq2_rptr[ASIZE-2:0]}); //:ASIZE-1]
5 T! T3 i2 c2 `8 `5 Talways @(posedge wclk or negedge wrst_n) & d! @2 z5 D( t5 {) H# F
if (!wrst_n) wfull <= 1'b0; 2 t3 d: r+ ~8 q L
else wfull <= wfull_val; 6 {( v: J& d |/ v/ i3 e
endmodule" |+ P0 V* m9 F( H( L- u! I; V, ~
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[ 本帖最後由 xuduo6845 於 2009-9-4 11:25 AM 編輯 ] |
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