add auto cpu frequency

When this feature enabled:
* Frequency sets to 14MHz on esxdos activity - for fastest loading from
sd card;
* Frequency sets to 3.5MHz within ~1ms after #FE port access - this
allows to load from tape within turbo mode. Also this improves beeper
sound effects;
* Otherwise user configured frequency is used.

cpld/rtl/magic.sv

@@ -2,6 +2,7 @@ import common::*;
 module magic(
     input rst_n,
     input clk28,
+    input ck35,
 
     cpu_bus bus,
     output [7:0] d_out,
@@ -102,6 +103,8 @@ end
 
 
 /* MAGIC CONFIG */
+turbo_t turbo0;
+reg autoturbo_en;
 wire config_cs = magic_map && bus.ioreq && bus.a[7:0] == 8'hFF;
 always @(posedge clk28 or negedge rst_n) begin
     if (!rst_n) begin
@@ -109,7 +112,7 @@ always @(posedge clk28 or negedge rst_n) begin
         magic_beeper <= 0;
         rom_wren <= 0;
         machine <= MACHINE_PENT;
-        turbo <= TURBO_NONE;
+        turbo0 <= TURBO_NONE;
         panning <= PANNING_ABC;
         rom_custom_en <= 0;
         rom_custom <= 0;
@@ -128,11 +131,12 @@ always @(posedge clk28 or negedge rst_n) begin
         `else
             bright_boost <= 1'b0;
         `endif
+        autoturbo_en <= 1'b0;
     end
     else if (config_cs && bus.wr) case (bus.a[15:8])
         8'h01: {rom_wren, magic_reboot, magic_beeper} <= bus.d[2:0];
         8'h02: machine <= machine_t'(bus.d[2:0]);
-        8'h03: turbo <= turbo_t'(bus.d[2:0]);
+        8'h03: turbo0 <= turbo_t'(bus.d[2:0]);
         8'h04: panning <= panning_t'(bus.d[1:0]);
         8'h05: {rom_custom_en, rom_custom} <= {bus.d[7], bus.d[1:0]};
         8'h06: {rom_alt48_en, rom_alt48} <= {bus.d[0] | bus.d[1], bus.d[1]};
@@ -143,6 +147,7 @@ always @(posedge clk28 or negedge rst_n) begin
         8'h0B: {soundrive_en, covox_en} <= bus.d[1:0];
         8'h0C: sd_indication_en <= bus.d[0];
         8'h0D: bright_boost <= bus.d[0];
+        8'h0E: autoturbo_en <= bus.d[0];
     endcase
 end
 
@@ -156,6 +161,28 @@ always @(posedge clk28 or negedge rst_n) begin
 end
 
 
+/* AUTOMATIC TURBO */
+reg [11:0] portfe_noturbo; // 1170uS
+always @(posedge clk28 or negedge rst_n) begin
+    if (!rst_n)
+        portfe_noturbo <= 0;
+    else if (bus.ioreq && !bus.a[0])
+        portfe_noturbo <= 1'b1;
+    else if (|portfe_noturbo && ck35)
+        portfe_noturbo <= portfe_noturbo + 1'b1;
+end
+always @(posedge clk28 or negedge rst_n) begin
+    if (!rst_n)
+        turbo <= TURBO_NONE;
+    else if (autoturbo_en && div_paged && !magic_map)
+        turbo <= TURBO_14;
+    else if (autoturbo_en && |portfe_noturbo)
+        turbo <= TURBO_NONE;
+    else
+        turbo <= turbo0;
+end
+
+
 /* BUS CONTROLLER */
 assign d_out_active = config_rd;
 assign d_out = config_data;

cpld/rtl/top.sv

@@ -336,6 +336,7 @@ assign sd_indication = sd_indication_en & ~sd_cs;
 magic magic0(
     .rst_n(n_rstcpu_in),
     .clk28(clk28),
+    .ck35(ck35),
 
     .bus(bus),
     .d_out(magic_dout),

rom_src/config.asm

@@ -43,6 +43,7 @@ ulaplus    DB 1
 dac        DB 3
 sdind      DB 1
 bright     DB BRIGHT_DEFAULT
+autoturbo  DB 0
 ENDIF
     ENDS
 

rom_src/menu_structure.asm

@@ -63,6 +63,7 @@ menuext: MENU_DEF 20
 menuadv: MENU_DEF 22
     MENUENTRY_T str_sd_indication menu_sdind_value_cb     menu_sdind_cb
     MENUENTRY_T str_bright_boost  menu_bright_value_cb    menu_bright_cb
+    MENUENTRY_T str_autoturbo     menu_autoturbo_value_cb menu_autoturbo_cb
     MENUENTRY_T str_save_settings menu_cfgsave_value_cb   menu_cfgsave_cb
     MENUENTRY_T str_back          0                       menu_back_cb
     MENUENTRY_T 0
@@ -215,6 +216,14 @@ menu_bright_value_cb:
     DW str_off_short_end-2
     DW str_on_short_end-2
 
+menu_autoturbo_value_cb:
+    ld ix, .values_table
+    ld a, (cfg.autoturbo)
+    jp menu_value_get
+.values_table:
+    DW str_off_short_end-2
+    DW str_on_short_end-2
+
 menu_cfgsave_value_cb:
     ld ix, .values_table
     ld a, (var_flash_error)
@@ -385,6 +394,15 @@ menu_bright_cb:
     out (c), a
     ret
 
+menu_autoturbo_cb:
+    ld a, (cfg.autoturbo)
+    ld c, 1
+    call menu_handle_press
+    ld (cfg.autoturbo), a
+    ld bc, #0eff
+    out (c), a
+    ret
+
 menu_cfgsave_cb:
     bit 4, d                ; action?
     ret z
@@ -397,7 +415,7 @@ menu_cfgsave_cb:
 .loop:                          ; ...
     push bc                     ; ...
     call .save_animation_effect ; ...
-    pop bc                      ; ... 
+    pop bc                      ; ...
     djnz .loop                  ; ...
     pop de
     ret
@@ -414,7 +432,7 @@ menu_cfgsave_cb:
     jr nz, .loop_inner
     dec e
     jr nz, .loop_outer
-    ret    
+    ret
 
 menu_back_cb:
     call restore_screen
@@ -425,7 +443,7 @@ menu_boot_normal_cb:
     bit 4, d                ; action?
     ret z
     ld a, 0
-    ld (cfg_saved.custom_rom), a 
+    ld (cfg_saved.custom_rom), a
     ld a, 1
     ld (var_exit_flag), a
     ret
@@ -434,7 +452,7 @@ menu_boot_zx80_cb:
     bit 4, d                ; action?
     ret z
     ld a, #81
-    ld (cfg_saved.custom_rom), a 
+    ld (cfg_saved.custom_rom), a
     ld a, 1
     ld (var_exit_flag), a
     ret
@@ -443,7 +461,7 @@ menu_boot_zx81_cb:
     bit 4, d                ; action?
     ret z
     ld a, #80
-    ld (cfg_saved.custom_rom), a 
+    ld (cfg_saved.custom_rom), a
     ld a, 1
     ld (var_exit_flag), a
     ret
@@ -452,7 +470,7 @@ menu_boot_negluk_cb:
     bit 4, d                ; action?
     ret z
     ld a, #83
-    ld (cfg_saved.custom_rom), a 
+    ld (cfg_saved.custom_rom), a
     ld a, 1
     ld (var_exit_flag), a
     ret
@@ -486,4 +504,3 @@ menu_handle_press:
 .decrement_roll:
     ld a, c                 ; value = max
     ret
-

rom_src/strings.asm

@@ -135,6 +135,9 @@ str_sd_indication_end:
 str_bright_boost: DB "Bright boost",0
 str_bright_boost_end:
 
+str_autoturbo: DB "Auto CPU freq",0
+str_autoturbo_end:
+
 str_save_settings: DB "Save settings",0
 str_save_settings_end:
 
@@ -158,4 +161,3 @@ str_zx81_end:
 
 str_negluk: DB "HE GLUK",0
 str_negluk_end:
-