Update comments in abc9_map.v

This commit is contained in:
Eddie Hung 2019-10-07 12:54:45 -07:00
parent 1dc22607c3
commit bae3d8705d
1 changed files with 57 additions and 131 deletions

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@ -28,12 +28,53 @@
// ============================================================================ // ============================================================================
// The purpose of the following FD* rules are to wrap the flop (which, when // `abc9' requires that complex flops be split into a combinatorial box
// called with the `_ABC' macro set captures only its combinatorial // feeding a simple flop ($_ABC9_FF_).
// behaviour) with: // Yosys will automatically analyse the simulation model (described in
// cells_sim.v) and detach any $_DFF_P_ or $_DFF_N_ cells present in
// order to extract the combinatorial control logic left behind.
// Specifically, a simulation model similar to the one below:
//
// ++===================================++
// || Sim model ||
// || /\/\/\/\ ||
// D -->>-----< > +------+ ||
// R -->>-----< Comb. > |$_DFF_| ||
// CE -->>-----< logic >-----| [NP]_|---+---->>-- Q
// || +--< > +------+ | ||
// || | \/\/\/\/ | ||
// || | | ||
// || +----------------------------+ ||
// || ||
// ++===================================++
//
// is transformed into:
//
// ++==================++
// || Comb box ||
// || ||
// || /\/\/\/\ ||
// D -->>-----< > || +------+
// R -->>-----< Comb. > || |$_ABC_|
// CE -->>-----< logic >--->>-- $nextQ --| FF_ |--+-->> Q
// $currQ +-->>-----< > || +------+ |
// | || \/\/\/\/ || |
// | || || |
// | ++==================++ |
// | |
// +----------------------------------------------+
//
// The purpose of the following FD* rules are to wrap the flop with:
// (a) a special $__ABC9_FF_ in front of the FD*'s output, indicating to abc9 // (a) a special $__ABC9_FF_ in front of the FD*'s output, indicating to abc9
// the connectivity of its basic D-Q flop // the connectivity of its basic D-Q flop
// (b) a special TECHMAP_REPLACE_.$currQ wire that will be used for feedback // (b) a special _TECHMAP_REPLACE_.$abc9_clock wire to capture its clock
// domain (used when partitioning the module so that `abc9' only
// performs sequential synthesis (with reachability analysis) correctly on
// one domain at a time)
// (c) a special _TECHMAP_REPLACE_.$abc9_control that captures the control
// domain (which, combined with this cell type, encodes to `abc9' which
// flops may be merged together)
// (d) a special _TECHMAP_REPLACE_.$currQ wire that will be used for feedback
// into the (combinatorial) FD* cell to facilitate clock-enable behaviour // into the (combinatorial) FD* cell to facilitate clock-enable behaviour
module FDRE (output reg Q, input C, CE, D, R); module FDRE (output reg Q, input C, CE, D, R);
parameter [0:0] INIT = 1'b0; parameter [0:0] INIT = 1'b0;
@ -49,56 +90,11 @@ module FDRE (output reg Q, input C, CE, D, R);
) _TECHMAP_REPLACE_ ( ) _TECHMAP_REPLACE_ (
.D(D), .Q($nextQ), .C(C), .CE(CE), .R(R) .D(D), .Q($nextQ), .C(C), .CE(CE), .R(R)
); );
// `abc9' requires that complex flops be split into a combinatorial box
// feeding a simple flop ($_ABC9_FF_).
// Yosys will automatically analyse the simulation model (described in
// cells_sim.v) and detach any $_DFF_P_ or $_DFF_N_ cells present in
// order to extract the combinatorial control logic left behind.
// Specifically, a simulation model similar to the one below:
//
// ++===================================++
// || Sim model ||
// || /\/\/\/\ ||
// D -->>-----< > +------+ ||
// R -->>-----< Comb. > |$_DFF_| ||
// CE -->>-----< logic >-----| [NP]_|---+---->>-- Q
// || +--< > +------+ | ||
// || | \/\/\/\/ | ||
// || | | ||
// || +----------------------------+ ||
// || ||
// ++===================================++
//
// is transformed into:
//
// ++==================++
// || Comb box ||
// || ||
// || /\/\/\/\ ||
// D -->>-----< > || +------+
// R -->>-----< Comb. > || |$_ABC_|
// CE -->>-----< logic >--->>-- $nextQ --| FF_ |--+-->> Q
// $currQ +-->>-----< > || +------+ |
// | || \/\/\/\/ || |
// | || || |
// | ++==================++ |
// | |
// +----------------------------------------------+
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED};
// Special signal indicating control domain
// (which, combined with this cell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, R, IS_R_INVERTED}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, R, IS_R_INVERTED};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = Q; wire _TECHMAP_REPLACE_.$currQ = Q;
endmodule endmodule
module FDRE_1 (output reg Q, input C, CE, D, R); module FDRE_1 (output reg Q, input C, CE, D, R);
@ -111,19 +107,9 @@ module FDRE_1 (output reg Q, input C, CE, D, R);
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, R, 1'b0 /* IS_R_INVERTED */}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, R, 1'b0 /* IS_R_INVERTED */};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = Q; wire _TECHMAP_REPLACE_.$currQ = Q;
endmodule endmodule
@ -142,7 +128,7 @@ module FDCE (output reg Q, input C, CE, D, CLR);
.D(D), .Q($nextQ), .C(C), .CE(CE), .CLR(IS_CLR_INVERTED) .D(D), .Q($nextQ), .C(C), .CE(CE), .CLR(IS_CLR_INVERTED)
// ^^^ Note that async // ^^^ Note that async
// control is disabled // control is disabled
// and captured by // here but captured by
// $__ABC9_ASYNC below // $__ABC9_ASYNC below
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ));
@ -150,19 +136,9 @@ module FDCE (output reg Q, input C, CE, D, CLR);
// using the $_ABC9_ASYNC box by abc9_map.v // using the $_ABC9_ASYNC box by abc9_map.v
\$__ABC9_ASYNC abc_async (.A($currQ), .S(CLR ^ IS_CLR_INVERTED), .Y(Q)); \$__ABC9_ASYNC abc_async (.A($currQ), .S(CLR ^ IS_CLR_INVERTED), .Y(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, CLR, IS_CLR_INVERTED}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, CLR, IS_CLR_INVERTED};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = $currQ; wire _TECHMAP_REPLACE_.$currQ = $currQ;
endmodule endmodule
module FDCE_1 (output reg Q, input C, CE, D, CLR); module FDCE_1 (output reg Q, input C, CE, D, CLR);
@ -174,25 +150,15 @@ module FDCE_1 (output reg Q, input C, CE, D, CLR);
.D(D), .Q($nextQ), .C(C), .CE(CE), .CLR(1'b0) .D(D), .Q($nextQ), .C(C), .CE(CE), .CLR(1'b0)
// ^^^ Note that async // ^^^ Note that async
// control is disabled // control is disabled
// and captured by // here but captured by
// $__ABC9_ASYNC below // $__ABC9_ASYNC below
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ));
\$__ABC9_ASYNC abc_async (.A($currQ), .S(CLR), .Y(Q)); \$__ABC9_ASYNC abc_async (.A($currQ), .S(CLR), .Y(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, CLR, 1'b0 /* IS_CLR_INVERTED */}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, CLR, 1'b0 /* IS_CLR_INVERTED */};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = $currQ; wire _TECHMAP_REPLACE_.$currQ = $currQ;
endmodule endmodule
@ -211,25 +177,15 @@ module FDPE (output reg Q, input C, CE, D, PRE);
.D(D), .Q($nextQ), .C(C), .CE(CE), .PRE(IS_PRE_INVERTED) .D(D), .Q($nextQ), .C(C), .CE(CE), .PRE(IS_PRE_INVERTED)
// ^^^ Note that async // ^^^ Note that async
// control is disabled // control is disabled
// and captured by // here but captured by
// $__ABC9_ASYNC below // $__ABC9_ASYNC below
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ));
\$__ABC9_ASYNC abc_async (.A($currQ), .S(PRE ^ IS_PRE_INVERTED), .Y(Q)); \$__ABC9_ASYNC abc_async (.A($currQ), .S(PRE ^ IS_PRE_INVERTED), .Y(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, PRE, IS_PRE_INVERTED}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, PRE, IS_PRE_INVERTED};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = $currQ; wire _TECHMAP_REPLACE_.$currQ = $currQ;
endmodule endmodule
module FDPE_1 (output reg Q, input C, CE, D, PRE); module FDPE_1 (output reg Q, input C, CE, D, PRE);
@ -241,25 +197,15 @@ module FDPE_1 (output reg Q, input C, CE, D, PRE);
.D(D), .Q($nextQ), .C(C), .CE(CE), .PRE(1'b0) .D(D), .Q($nextQ), .C(C), .CE(CE), .PRE(1'b0)
// ^^^ Note that async // ^^^ Note that async
// control is disabled // control is disabled
// and captured by // here but captured by
// $__ABC9_ASYNC below // $__ABC9_ASYNC below
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q($currQ));
\$__ABC9_ASYNC abc_async (.A($currQ), .S(PRE), .Y(Q)); \$__ABC9_ASYNC abc_async (.A($currQ), .S(PRE), .Y(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, PRE, 1'b0 /* IS_PRE_INVERTED */}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, PRE, 1'b0 /* IS_PRE_INVERTED */};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = $currQ; wire _TECHMAP_REPLACE_.$currQ = $currQ;
endmodule endmodule
@ -279,19 +225,9 @@ module FDSE (output reg Q, input C, CE, D, S);
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, IS_C_INVERTED};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, S, IS_S_INVERTED}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, IS_D_INVERTED, S, IS_S_INVERTED};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = Q; wire _TECHMAP_REPLACE_.$currQ = Q;
endmodule endmodule
module FDSE_1 (output reg Q, input C, CE, D, S); module FDSE_1 (output reg Q, input C, CE, D, S);
@ -304,19 +240,9 @@ module FDSE_1 (output reg Q, input C, CE, D, S);
); );
\$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q)); \$__ABC9_FF_ abc_dff (.D($nextQ), .Q(Q));
// Special signal indicating clock domain // Special signals
// (used to partition the module so that `abc9' only performs
// sequential synthesis (reachability analysis) correctly on
// one domain at a time)
wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */}; wire [1:0] _TECHMAP_REPLACE_.$abc9_clock = {C, 1'b1 /* IS_C_INVERTED */};
// Special signal indicating control domain
// (which, combined with this spell type, encodes to `abc9'
// which flops may be merged together)
wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, S, 1'b0 /* IS_S_INVERTED */}; wire [3:0] _TECHMAP_REPLACE_.$abc9_control = {CE, 1'b0 /* IS_D_INVERTED */, S, 1'b0 /* IS_S_INVERTED */};
// Special signal indicating the current value of the flip-flop
// In order to achieve clock-enable behaviour, the current value
// of the sequential output is required which Yosys will
// connect to the special `$currQ' wire.
wire _TECHMAP_REPLACE_.$currQ = Q; wire _TECHMAP_REPLACE_.$currQ = Q;
endmodule endmodule