From 329424619a2017aee9eaee3211944e249f059648 Mon Sep 17 00:00:00 2001
From: Alban Gruin <alban.gruin@irit.fr>
Date: Mon, 9 May 2022 13:06:32 +0200
Subject: [PATCH] Revert "sras: lock SRAS if there is too much calls"
This reverts commit 071fc948a90e2b781e666851868dd607192747cf.
---
src/frontend/sras.sv | 71 +++++++++++++-------------------------------
1 file changed, 21 insertions(+), 50 deletions(-)
diff --git a/src/frontend/sras.sv b/src/frontend/sras.sv
index 4f1aea3a..053f13ff 100644
--- a/src/frontend/sras.sv
+++ b/src/frontend/sras.sv
@@ -16,8 +16,7 @@
// segmented return address stack
module sras #(
parameter int unsigned DEPTH = 2,
- parameter int unsigned SpecDepth = 16,
- parameter int unsigned SZ_OVF = 16
+ parameter int unsigned SpecDepth = 16
)(
input logic clk_i,
input logic rst_ni,
@@ -35,7 +34,6 @@ module sras #(
logic [$clog2(SpecDepth)-1:0] ptr_backup_d, ptr_backup_q;
logic [SpecDepth-1:0][$clog2(DEPTH)-1:0] tos_d, tos_q;
ariane_pkg::ras_t [SpecDepth-1:0][DEPTH-1:0] stack_d, stack_q;
- logic [SpecDepth-1:0][SZ_OVF-1:0] ovf_counter_d, ovf_counter_q;
assign ptr_spec_d = (bad_spec_i) ? ptr_backup_q : (begin_spec_i) ? ptr_spec_q + 1'b1 : ptr_spec_q;
assign ptr_backup_d = (valid_spec_i) ? ptr_backup_q + 1'b1 : ptr_backup_q;
@@ -50,51 +48,26 @@ module sras #(
assign pp_plus_one = tos_q[ptr_spec_q] + 1'b1;
assign prev_minus_one = previous_tos - 1'b1;
- logic overflow;
- assign overflow = |ovf_counter_q[ptr_spec_q];
-
always_comb begin
tos_d = tos_q;
- ovf_counter_d = ovf_counter_q;
if (flush_i) begin
tos_d = '0;
- ovf_counter_d = '0;
- end else if (!bad_spec_i) begin
- if (push_i && !pop_i) begin
- if (overflow) begin
- ovf_counter_d[ptr_spec_d] = ovf_counter_q[ptr_spec_q] + 1'b1;
- end else begin
- if (prev_plus_one == '0 || pp_plus_one == '0) begin
- ovf_counter_d[ptr_spec_d] = ovf_counter_q[ptr_spec_q] + 1'b1;
- ovf_counter_d[ptr_spec_q] = ovf_counter_q[ptr_spec_q] + 1'b1;
- end else begin
- tos_d[ptr_spec_d] = prev_plus_one;
- tos_d[ptr_spec_q] = pp_plus_one;
- end
- end
- end else if (!push_i && pop_i) begin
- if (ovf_counter_q[ptr_spec_q] != '0) begin
- ovf_counter_d[ptr_spec_d] = ovf_counter_q[ptr_spec_q] - 1'b1;
- end else begin
- tos_d[ptr_spec_d] = prev_minus_one;
- end
- end else if (!bad_spec_i && begin_spec_i) begin
- tos_d[ptr_spec_d] = tos_q[ptr_spec_q];
- ovf_counter_d[ptr_spec_d] = ovf_counter_q[ptr_spec_q];
- end
+ end else if (push_i && !pop_i) begin
+ tos_d[ptr_spec_d] = prev_plus_one;
+ tos_d[ptr_spec_q] = pp_plus_one;
+ end else if (!push_i && pop_i) begin
+ tos_d[ptr_spec_d] = prev_minus_one;
+ end else if (!bad_spec_i && begin_spec_i) begin
+ tos_d[ptr_spec_d] = tos_q[ptr_spec_q];
end
end
- logic can_pop, can_push;
- assign can_pop = pop_i && ovf_counter_d[ptr_spec_q][SZ_OVF-1:1] == '0 && !bad_spec_i;
- assign can_push = push_i && ovf_counter_d[ptr_spec_q] == '0 && !bad_spec_i;
-
assign data_o = stack_q[previous_tos_addr][previous_tos];
ariane_pkg::ras_t to_push;
- assign to_push.ra = (can_push) ? data_i : 0;
- assign to_push.valid = can_push;
+ assign to_push.ra = (push_i) ? data_i : 0;
+ assign to_push.valid = push_i;
ariane_pkg::ras_t [DEPTH-1:0] new_stack, prev_stack;
@@ -105,11 +78,11 @@ module sras #(
new_stack = stack_q[ptr_spec_q];
end
- if (can_pop) begin
+ if (pop_i) begin
new_stack[previous_tos] = to_push;
end
- if (can_push) begin
+ if (push_i) begin
new_stack[prev_plus_one] = to_push;
end
end
@@ -117,7 +90,7 @@ module sras #(
always_comb begin
prev_stack = stack_q[ptr_spec_q];
- if (can_push) begin
+ if (push_i) begin
prev_stack[pp_plus_one] = to_push;
end
end
@@ -131,17 +104,15 @@ module sras #(
always_ff @(posedge clk_i or negedge rst_ni) begin
if (~rst_ni) begin
- stack_q <= '0;
- ptr_spec_q <= '0;
- ptr_backup_q <= '0;
- tos_q <= '0;
- ovf_counter_q <= '0;
+ stack_q <= '0;
+ ptr_spec_q <= '0;
+ ptr_backup_q <= '0;
+ tos_q <= '0;
end else begin
- stack_q <= stack_d;
- ptr_spec_q <= ptr_spec_d;
- ptr_backup_q <= ptr_backup_d;
- tos_q <= tos_d;
- ovf_counter_q <= ovf_counter_d;
+ stack_q <= stack_d;
+ ptr_spec_q <= ptr_spec_d;
+ ptr_backup_q <= ptr_backup_d;
+ tos_q <= tos_d;
end
end
--
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