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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.' Q7 I# j- G- |5 `( E& {
module fifo1(rdata, wfull, rempty, wdata, winc, wclk, wrst_n,rinc, rclk, rrst_n); 9 A2 w0 \5 v& }. [+ v$ z' h% g
parameter DSIZE = 8; parameter ASIZE = 4; % {! e$ S' I+ G! c# O- ]
output [DSIZE-1:0] rdata;
; G* W( R4 [4 J5 loutput wfull;
7 z! i2 G0 f0 K/ _output rempty;
2 _; Z5 b9 @& V0 cinput [DSIZE-1:0] wdata;
- M( T1 ^+ Y, M$ q" [input winc, wclk, wrst_n;
# X3 Z$ \. A# Y: m* Oinput rinc, rclk, rrst_n;
( a8 ]( {6 A0 T' w2 ereg wfull,rempty; 5 \% B$ J G' }1 E9 c: D v% n
reg [ASIZE:0] wptr, rptr, wq2_rptr, rq2_wptr, wq1_rptr,rq1_wptr;
7 t; A: Y( a' t2 t$ R' preg [ASIZE:0] rbin, wbin;
6 f' g! ?! |. e$ A" F9 Xreg [DSIZE-1:0] mem[0: (1<<ASIZE)-1];
( x9 e; _! }9 f# c+ wwire [ASIZE-1:0] waddr, raddr;
+ x% }9 ?3 `& W* z5 Cwire [ASIZE:0] rgraynext, rbinnext,wgraynext,wbinnext; 3 L& P- O7 Q$ `: @5 R; f
wire rempty_val,wfull_val;
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assign rdata=mem[raddr];
D0 Y p( G* L/ `- e7 Oalways@(posedge wclk)
) \+ J. V+ C) f; y5 Uif (winc && !wfull) mem[waddr] <= wdata;
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always @(posedge wclk or negedge wrst_n)
3 x% i+ R3 U( H4 cif (!wrst_n) {wq2_rptr,wq1_rptr} <= 0; 8 \4 R5 j( T# a6 g
else {wq2_rptr,wq1_rptr} <= {wq1_rptr,rptr};
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always @(posedge rclk or negedge rrst_n)
* Q6 g7 X) O0 q; Iif (!rrst_n) {rq2_wptr,rq1_wptr} <= 0;
6 j; D7 H* \9 O5 Oelse {rq2_wptr,rq1_wptr} <= {rq1_wptr,wptr}; , o2 V* B b4 @% k9 g' P
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always @(posedge rclk or negedge rrst_n) // GRAYSTYLE2 pointer # K$ A" ]3 N5 ~( P
begin
R6 A& P5 d& [/ ^, z+ Oif (!rrst_n) {rbin, rptr} <= 0; % L/ Z; t5 M# j7 G( j q. T) e
else {rbin, rptr} <= {rbinnext, rgraynext}; / U/ k/ W7 F y- n
end
0 P7 p* h9 v- [; d: q% u, v7 ~
7 j% B' o% \3 q massign raddr = rbin[ASIZE-1:0];
! m" D. U$ X2 vassign rbinnext = rbin + (rinc & ~rempty);
! G# T1 ^* M/ y0 l( j- rassign rgraynext = (rbinnext>>1) ^ rbinnext; 7 S; S$ d% D1 c3 m
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assign rempty_val = (rgraynext == rq2_wptr); 7 |& H0 o) v! y1 W$ ]! V; P& F
always @(posedge rclk or negedge rrst_n) - ?5 n: \: D, O5 g% W7 ?: N
begin
4 E( d, C" v) i/ i. [1 aif (!rrst_n) rempty <= 1'b1;
7 @, S ~! B( e. J2 J$ ? F, a5 P. welse rempty <= rempty_val; - q: S" g2 W, {* ^! W X& S
end
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* _) l* n& { V
always @(posedge wclk or negedge wrst_n) // GRAYSTYLE2 pointer ! \, z8 T- l0 J3 _% a# ?( n" x
if (!wrst_n) {wbin, wptr} <= 0; 4 d f% S# B0 T6 Y- C: a
else {wbin, wptr} <= {wbinnext, wgraynext};
+ U |- L% U" |0 |: }
5 O& W* v: s% I, Z- _- e6 i; T7 N- H" }
assign waddr = wbin[ASIZE-1:0];
5 v% P$ b/ M1 w4 a% ], xassign wbinnext = wbin + (winc & ~wfull);
8 r, P* R. S6 S sassign wgraynext = (wbinnext>>1) ^ wbinnext; 5 g* d: ^+ j& B
assign wfull_val = (wgraynext=={~wq2_rptr[ASIZE:ASIZE-1], wq2_rptr[ASIZE-2:0]}); //:ASIZE-1]9 z' s% {6 T: }8 ?! k3 O
always @(posedge wclk or negedge wrst_n) ( x/ g N" f$ f: b, N8 n/ h' R
if (!wrst_n) wfull <= 1'b0; # C8 _& K: p6 y+ Y
else wfull <= wfull_val;
& \* J* W! T* K! A4 Oendmodule
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[ 本帖最後由 xuduo6845 於 2009-9-4 11:25 AM 編輯 ] |
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