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Update sys.

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Sorgelig
2023-12-08 17:08:13 +08:00
parent dcaed90e6d
commit d88b97d957
3 changed files with 69 additions and 21 deletions
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46
sys/video_freak.sv
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@ -173,7 +173,7 @@ sys_umul #(12,12) mul(CLK_VIDEO,mul_start,mul_run, mul_arg1,mul_arg2,mul_res);
wire [11:0] wideres = mul_res[11:0] + hsize;
always @(posedge CLK_VIDEO) begin
reg [11:0] oheight,wres;
reg [11:0] oheight,htarget,wres;
reg [12:0] arxf,aryf;
reg [3:0] cnt;
reg narrow;
@ -188,11 +188,18 @@ always @(posedge CLK_VIDEO) begin
else if(~div_start & ~div_run & ~mul_start & ~mul_run) begin
cnt <= cnt + 1'd1;
case(cnt)
// example ideal and non-ideal cases:
// [1] 720x400 4:3 VGA 80x25 text-mode (non-square pixels)
// [2] 640x480 4:3 VGA graphics mode (square pixels)
// [3] 512x512 4:3 X68000 graphics mode (non-square pixels)
0: begin
div_num <= HDMI_HEIGHT;
div_den <= vsize;
div_start <= 1;
end
// [1] 1080 / 400 -> 2
// [2] 1080 / 480 -> 2
// [3] 1080 / 512 -> 2
1: if(!div_res[11:0]) begin
// screen resolution is lower than video resolution.
@ -206,6 +213,9 @@ always @(posedge CLK_VIDEO) begin
mul_arg2 <= div_res[11:0];
mul_start <= 1;
end
// [1] 1080 / 400 * 400 -> 800
// [2] 1080 / 480 * 480 -> 960
// [3] 1080 / 512 * 512 -> 1024
2: begin
oheight <= mul_res[11:0];
@ -219,24 +229,39 @@ always @(posedge CLK_VIDEO) begin
mul_arg2 <= arx_i;
mul_start <= 1;
end
// [1] 1080 / 400 * 400 * 4 -> 3200
// [2] 1080 / 480 * 480 * 4 -> 3840
// [3] 1080 / 512 * 512 * 4 -> 4096
4: begin
div_num <= mul_res;
div_den <= ary_i;
div_start <= 1;
end
// [1] 1080 / 480 * 480 * 4 / 3 -> 1066
// [2] 1080 / 480 * 480 * 4 / 3 -> 1280
// [3] 1080 / 512 * 512 * 4 / 3 -> 1365
// saved as htarget
5: begin
htarget <= div_res[11:0];
div_num <= div_res;
div_den <= hsize;
div_start <= 1;
end
// computes wide scaling factor as a ceiling division
// [1] 1080 / 400 * 400 * 4 / 3 / 720 -> 1
// [2] 1080 / 480 * 480 * 4 / 3 / 640 -> 2
// [3] 1080 / 512 * 512 * 4 / 3 / 512 -> 2
6: begin
mul_arg1 <= hsize;
mul_arg2 <= div_res[11:0] ? div_res[11:0] : 12'd1;
mul_start <= 1;
end
// [1] 1080 / 400 * 400 * 4 / 3 / 720 * 720 -> 720
// [2] 1080 / 480 * 480 * 4 / 3 / 640 * 640 -> 1280
// [3] 1080 / 512 * 512 * 4 / 3 / 512 * 512 -> 1024
7: if(mul_res <= HDMI_WIDTH) begin
cnt <= 10;
@ -247,17 +272,32 @@ always @(posedge CLK_VIDEO) begin
div_den <= hsize;
div_start <= 1;
end
// [1] 1920 / 720 -> 2
// [2] 1920 / 640 -> 3
// [3] 1920 / 512 -> 3
9: begin
mul_arg1 <= hsize;
mul_arg2 <= div_res[11:0] ? div_res[11:0] : 12'd1;
mul_start <= 1;
end
// [1] 1920 / 720 * 720 -> 1440
// [2] 1920 / 640 * 640 -> 1920
// [3] 1920 / 512 * 512 -> 1536
10: begin
narrow <= ((div_num[11:0] - mul_res[11:0]) <= (wideres - div_num[11:0])) || (wideres > HDMI_WIDTH);
wres <= wideres;
narrow <= ((htarget - mul_res[11:0]) <= (wideres - htarget)) || (wideres > HDMI_WIDTH);
wres <= mul_res[11:0] == htarget ? mul_res[11:0] : wideres;
end
// [1] 1066 - 720 = 346 <= 1440 - 1066 = 374 || 1440 > 1920 -> true
// [2] 1280 - 1280 = 0 <= 1920 - 1280 = 640 || 1920 > 1920 -> true
// [3] 1365 - 1024 = 341 <= 1536 - 1365 = 171 || 1536 > 1920 -> false
// 1. narrow flag is true when mul_res[11:0] narrow width is closer to
// htarget aspect ratio target width or when wideres wider width
// does not fit to the screen.
// 2. wres becomes wideres only when mul_res[11:0] narrow width not equal
// to target width, meaning it is not optimal for source aspect ratio.
// otherwise it is set to narrow width that is optimal.
11: begin
case(SCALE)