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[ATARI ST] MFP irq patch. Fixes R-Type 1 splash screen

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This commit is contained in:
harbaum
2015-03-31 18:36:53 +00:00
parent dc5f8ef757
commit edffa94eac
1 changed files with 9 additions and 7 deletions
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16
cores/mist/mfp.v
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@@ -186,7 +186,7 @@ reg [15:0] imr, ier; // interrupt registers
reg [7:0] vr;
// generate irq signal if an irq is pending and no other irq of same or higher prio is in service
assign irq = ((ipr & imr) != 16'h0000) && (highest_irq_pending >= irq_in_service);
assign irq = ((ipr & imr) != 16'h0000) && (highest_irq_pending > irq_in_service);
// check number of current interrupt in service
wire [3:0] irq_in_service;
@@ -278,14 +278,13 @@ mfp_srff16 ipr_latch (
.reset ( ipr_reset ),
.out ( ipr )
);
// ------------------------ ISR register --------------------------
wire [15:0] isr;
reg [15:0] isr_reset;
reg [15:0] isr_set;
// move highest pending irq into isr when s bit set and iack raises
wire [15:0] isr_set = (vr[3] && iack)?highest_irq_pending_mask:16'h0000;
mfp_srff16 isr_latch (
.set ( isr_set ),
.reset ( isr_reset ),
@@ -307,12 +306,15 @@ always @(negedge clk) begin
isr_reset <= 16'hffff;
ier <= 16'h0000;
imr <= 16'h0000;
isr_set <= 16'h0000;
end else begin
// remove active bit from ipr
if(iack)
// remove active bit from ipr and set it in isr
if(iack) begin
ipr_reset[highest_irq_pending] <= 1'b1;
isr_set <= (vr[3] && iack)?highest_irq_pending_mask:16'h0000;
end
if(sel && ~ds && ~rw) begin
// -------- GPIO ---------
if(addr == 5'h00) gpip <= din;