111.949MHz/1A7A: UART FIFO working

The UART FIFO is now working. This requires some changes to the UART
driver, and also how the PS/2 Keyboard interface works. It also has
introduced some difficulties in the simulator, the simulator now needs
to peek at the input stream in order to simulate the PS/2 and UART input
correctly, which is fine for the GUI application, but not so for the CLI
application. I may change how the FIFO works again so it is easier to
simulate. The problem is whether we read a character first and then
trigger a read enabled, or whether we do a read enable then read a
character.

Author: howerj

embed.fth

@@ -832,11 +832,17 @@ h: (irq)
   ien! ;
 [t] (irq) 2/ $C t!
 : irq $0040 $4010 ! [-1] timer! 1 ien! ;
+
+\ FIFO: Write Read Enable after Read
 h: uart? ( uart-register -- c -1 | 0 : generic UART input functions )
-  dup @ $0100 and if drop 0x0000 exit then dup $0400 swap ! @ $FF and [-1] ; 
+ dup @ $0100 and if drop 0x0000 exit then dup @ $FF and swap $0400 swap! [-1] ; 
+\ FIFO: Write Read Enable before Read
+\ h: uart? ( uart-register -- c -1 | 0 : generic UART input functions )
+\ dup @ $0100 and if drop 0x0000 exit then dup $0400 swap! @ $FF and [-1] ; 
+
 : rx?  $4000 uart? if [-1] exit then $4002 uart? ; ( -- c -1|0: rx uart/ps2 )
 h: uart! ( c uart-register -- )
-	begin dup @ $1000 and 0= until swap $2000 or swap ! ;
+	begin dup @ $1000 and 0= until swap $2000 or swap! ;
 : tx! dup $4002 uart! ( VGA/VT-100 ) $4000 uart! ( UART )  ;
 h: (ok) state@ if cr exit then ."  ok" cr ;  ( -- : default state aware prompt )
 h: preset tib-start #tib cell+ ! 0 in! id zero ;  ( -- : reset input )

gui.c

@@ -851,7 +851,18 @@ static fifo_t *ps2_rx_fifo = NULL;
 
 /* ====================================== H2 I/O Handling ====================================== */
 
-static uint16_t h2_io_get_gui(const h2_soc_state_t * const soc, const uint16_t addr, bool *debug_on) {
+static void fifo_peek(fifo_t *f, fifo_data_t *data) {
+	assert(f);
+	assert(data);
+	assert(sizeof(*data) == sizeof(uint8_t));
+	*data = 0;
+	if (fifo_is_empty(f))
+		return;
+	fifo_pop(f,   data);
+	fifo_push(f, *data);
+}
+
+static uint16_t h2_io_get_gui(h2_soc_state_t * const soc, const uint16_t addr, bool *debug_on) {
 	assert(soc);
 	assert(ps2_rx_fifo);
 	assert(uart_tx_fifo);
@@ -860,13 +871,16 @@ static uint16_t h2_io_get_gui(const h2_soc_state_t * const soc, const uint16_t a
 	if (debug_on)
 		*debug_on = false;
 	switch (addr) {
-	case iUart:
+	case iUart: {
+		fifo_peek(uart_rx_fifo, &soc->uart_getchar_register);
 		return (fifo_is_empty(uart_tx_fifo) << UART_TX_FIFO_EMPTY_BIT)
 			| (fifo_is_full(uart_tx_fifo)  << UART_TX_FIFO_FULL_BIT)
 			| (fifo_is_empty(uart_rx_fifo) << UART_RX_FIFO_EMPTY_BIT)
 			| (fifo_is_full(uart_rx_fifo)  << UART_RX_FIFO_FULL_BIT)
 			| soc->uart_getchar_register;
+	}
 	case iVT100:
+		fifo_peek(ps2_rx_fifo, &soc->ps2_getchar_register);
 		return (1u << UART_TX_FIFO_EMPTY_BIT)
 			| (0u << UART_TX_FIFO_FULL_BIT)
 			| (fifo_is_empty(ps2_rx_fifo) << UART_RX_FIFO_EMPTY_BIT)
@@ -883,7 +897,6 @@ static uint16_t h2_io_get_gui(const h2_soc_state_t * const soc, const uint16_t a
 	return 0;
 }
 
-/**@warning uses variables of static storage duration! */
 static void h2_io_set_gui(h2_soc_state_t *soc, const uint16_t addr, const uint16_t value, bool *debug_on) {
 	assert(soc);
 	assert(uart_tx_fifo);
@@ -931,9 +944,9 @@ static void h2_io_set_gui(h2_soc_state_t *soc, const uint16_t addr, const uint16
 	case oMemControl:
 		{
 			soc->mem_control    = value;
-			const bool sram_cs   = soc->mem_control & SRAM_CHIP_SELECT;
-			const bool oe        = soc->mem_control & FLASH_MEMORY_OE;
-			const bool we        = soc->mem_control & FLASH_MEMORY_WE;
+			const bool sram_cs  = soc->mem_control & SRAM_CHIP_SELECT;
+			const bool oe       = soc->mem_control & FLASH_MEMORY_OE;
+			const bool we       = soc->mem_control & FLASH_MEMORY_WE;
 			if (sram_cs && !oe && we)
 				soc->vram[(((uint32_t)(soc->mem_control & FLASH_MASK_ADDR_UPPER_MASK) << 16) | soc->mem_addr_low) >> 1] = soc->mem_dout;
 			break;

h2.c

@@ -1551,7 +1551,9 @@ uint16_t h2_io_memory_read_operation(const h2_soc_state_t * const soc) {
 	return 0;
 }
 
-static uint16_t h2_io_get_default(const h2_soc_state_t * const soc, const uint16_t addr, bool *debug_on) {
+/* TODO: Fix Input so Read then Read Enable FIFO semantics work
+   (this requires peeking at the input stream). */
+static uint16_t h2_io_get_default(h2_soc_state_t * const soc, const uint16_t addr, bool *debug_on) {
 	assert(soc);
 	debug("IO read addr: %"PRIx16, addr);
 	(void)debug_on;

h2.h

@@ -235,7 +235,7 @@ typedef struct {
 	uint16_t uart_tx_baud, uart_rx_baud, uart_control;
 } h2_soc_state_t;
 
-typedef uint16_t (*h2_io_get)(const h2_soc_state_t *soc, uint16_t addr, bool *debug_on);
+typedef uint16_t (*h2_io_get)(h2_soc_state_t *soc, uint16_t addr, bool *debug_on);
 typedef void     (*h2_io_set)(h2_soc_state_t *soc, uint16_t addr, uint16_t value, bool *debug_on);
 typedef void     (*h2_io_update)(h2_soc_state_t *soc);
 

kbd.vhd

@@ -104,7 +104,6 @@ architecture rtl of keyboard  is
 	signal kbd_new_edge: std_ulogic := '0';
 	signal kbd_new:      std_ulogic := '0'; -- new ASCII char available
 	signal kbd_char:     std_ulogic_vector(kbd_char_buf'range) := (others => '0'); -- ASCII char
-	signal kbd_char_o:   std_ulogic_vector(kbd_char_buf'range) := (others => '0'); -- ASCII char
 begin
 	kbd_char_buf_new <= kbd_new_c after g.delay;
 
@@ -128,15 +127,6 @@ begin
 		rst => rst,
 		di  => kbd_char,
 		we  => kbd_new_edge,
-		do  => kbd_char_o);
-
-	char_buf: entity work.reg
-	generic map(g => g, N => kbd_char'length)
-	port map(
-		clk => clk,
-		rst => rst,
-		di  => kbd_char_o,
-		we  => kbd_char_re,
 		do  => kbd_char_buf);
 
 	ps2_proc: process(kbd_new_edge, kbd_new_c, kbd_char_re)

t/ansi.fth

@@ -1,72 +1,72 @@
-\ RJH - ANSI TERMINAL TESTS / 2019. TESTED IN GFORTH
-\ Based around the definition for 'F' found here:
-\ https://www.forth.com/starting-forth/1-forth-stacks-dictionary/
-\
-\ This file is used to prepare test vectors for the VT-100 terminal emulator,
-\ a mini-language is make for drawing text and displaying colors.
-\
-ONLY FORTH DEFINITIONS DECIMAL
-
-WORDLIST CONSTANT COOL-TEXT ( <_< - way cool )
-COOL-TEXT >ORDER DEFINITIONS
-VARIABLE COOL-CHARACTER CHAR * COOL-CHARACTER !
-: BYE BYE ;
-: CR $D EMIT $A EMIT ;
-: {{ CR COOL-TEXT >ORDER DUP ;
-: >_> CHAR COOL-CHARACTER ! ;
-: <_< [CHAR] * COOL-CHARACTER ! ;
-: \ POSTPONE \ ;
-: .( POSTPONE .( ;
-
-: CSI $1B EMIT [CHAR] [ EMIT ; 
-: 10U. BASE @ >R DECIMAL 0 <# #S #> TYPE R> BASE ! ;
-: ANSI SWAP CSI 10U. EMIT ; ( N C -- )
-: AT-XY CSI 10U. $3B EMIT 10U. [CHAR] H EMIT ;
-: PAGE 2 [CHAR] J ANSI 1 1 AT-XY ;
-: SGR [CHAR] m ANSI ;
-
-: UP    [CHAR] A ANSI ;
-: DOWN  [CHAR] B ANSI ;
-: RIGHT [CHAR] C ANSI ;
-: LEFT  [CHAR] D ANSI ;
-
-0 CONSTANT BLACK 1 CONSTANT RED 2 CONSTANT GREEN 4 CONSTANT BLUE
-RED GREEN        + CONSTANT YELLOW
-    GREEN BLUE   + CONSTANT CYAN
-RED       BLUE   + CONSTANT MAGENTA
-RED GREEN BLUE + + CONSTANT WHITE
-: BACKGROUND $A + ;
-: COLOR $1E + SGR ;
-
-: BLINKY $5 SGR ;
-: UNBLINK $19 SGR ;
-: BOLD   $1  SGR ;
-: NORMAL $16 SGR ;
-: REVERSE $7 SGR ;
-: ESREVER $1B SGR ;
-
-: DOT     COOL-CHARACTER @ EMIT ;
-: DOTS    0 DO  DOT   LOOP ;
-: BLIP    1 DOWN DUP RIGHT    DOT DUP 2 * LEFT ;
-: BAR     1 DOWN DUP RIGHT 5 DOTS DUP 2 * LEFT ;
-: F       BAR BLIP BAR BLIP BLIP DROP 5 UP ;
-: C       BAR BLIP BLIP BLIP BAR DROP 5 UP ;
-: E       DUP F C ;
-: I       BLIP BLIP BLIP BLIP BLIP DROP 5 UP ;
-: O       DUP C 4 + I ;
-: A       DUP F 4 + I ;
-: _       4 DOWN BAR DROP 5 UP ;
-: TOP     BAR DROP 1 UP ;
-: U       DUP I DUP _ 4 + I ;
-: J       DUP _ 4 + I ;
-: L       DUP I _ ;
-: W       DUP L DUP 2 + I 4 + I ;
-: M       DUP I DUP 2 + I DUP 4 + I TOP ;
-: -       2 DOWN BAR DROP 3 UP ;
-: H       DUP I DUP - 4 + I ;
-: T       DUP TOP 2 + I ;
-: D       DUP I DROP ;
-
-: |       7 + DUP ;
-: }} DROP 6 DOWN PREVIOUS ;
-SEAL
+\ RJH - ANSI TERMINAL TESTS / 2019. TESTED IN GFORTH
+\ Based around the definition for 'F' found here:
+\ https://www.forth.com/starting-forth/1-forth-stacks-dictionary/
+\
+\ This file is used to prepare test vectors for the VT-100 terminal emulator,
+\ a mini-language is make for drawing text and displaying colors.
+\
+ONLY FORTH DEFINITIONS DECIMAL
+
+WORDLIST CONSTANT COOL-TEXT ( <_< - way cool )
+COOL-TEXT >ORDER DEFINITIONS
+VARIABLE COOL-CHARACTER CHAR * COOL-CHARACTER !
+: BYE BYE ;
+: CR $D EMIT $A EMIT ;
+: {{ CR COOL-TEXT >ORDER DUP ;
+: >_> CHAR COOL-CHARACTER ! ;
+: <_< [CHAR] * COOL-CHARACTER ! ;
+: \ POSTPONE \ ;
+: .( POSTPONE .( ;
+
+: CSI $1B EMIT [CHAR] [ EMIT ; 
+: 10U. BASE @ >R DECIMAL 0 <# #S #> TYPE R> BASE ! ;
+: ANSI SWAP CSI 10U. EMIT ; ( N C -- )
+: AT-XY CSI 10U. $3B EMIT 10U. [CHAR] H EMIT ;
+: PAGE 2 [CHAR] J ANSI 1 1 AT-XY ;
+: SGR [CHAR] m ANSI ;
+
+: UP    [CHAR] A ANSI ;
+: DOWN  [CHAR] B ANSI ;
+: RIGHT [CHAR] C ANSI ;
+: LEFT  [CHAR] D ANSI ;
+
+0 CONSTANT BLACK 1 CONSTANT RED 2 CONSTANT GREEN 4 CONSTANT BLUE
+RED GREEN        + CONSTANT YELLOW
+    GREEN BLUE   + CONSTANT CYAN
+RED       BLUE   + CONSTANT MAGENTA
+RED GREEN BLUE + + CONSTANT WHITE
+: BACKGROUND $A + ;
+: COLOR $1E + SGR ;
+
+: BLINKY $5 SGR ;
+: UNBLINK $19 SGR ;
+: BOLD   $1  SGR ;
+: NORMAL $16 SGR ;
+: REVERSE $7 SGR ;
+: ESREVER $1B SGR ;
+
+: DOT     COOL-CHARACTER @ EMIT ;
+: DOTS    0 DO  DOT   LOOP ;
+: BLIP    1 DOWN DUP RIGHT    DOT DUP 2 * LEFT ;
+: BAR     1 DOWN DUP RIGHT 5 DOTS DUP 2 * LEFT ;
+: F       BAR BLIP BAR BLIP BLIP DROP 5 UP ;
+: C       BAR BLIP BLIP BLIP BAR DROP 5 UP ;
+: E       DUP F C ;
+: I       BLIP BLIP BLIP BLIP BLIP DROP 5 UP ;
+: O       DUP C 4 + I ;
+: A       DUP F 4 + I ;
+: _       4 DOWN BAR DROP 5 UP ;
+: TOP     BAR DROP 1 UP ;
+: U       DUP I DUP _ 4 + I ;
+: J       DUP _ 4 + I ;
+: L       DUP I _ ;
+: W       DUP L DUP 2 + I 4 + I ;
+: M       DUP I DUP 2 + I DUP 4 + I TOP ;
+: -       2 DOWN BAR DROP 3 UP ;
+: H       DUP I DUP - 4 + I ;
+: T       DUP TOP 2 + I ;
+: D       DUP I DROP ;
+
+: |       7 + DUP ;
+: }} DROP 6 DOWN PREVIOUS ;
+SEAL

t/eforth.fth

@@ -1,3 +1,7 @@
 \ Test setup code for eForth interpreter on the target
+echos
+
+
+system +order
 : echos begin key emit switches until ;
 echos

tb.vhd

@@ -35,8 +35,7 @@ architecture testing of tb is
 	constant g: common_generics := (
 		clock_frequency    => 100_000_000,
 		asynchronous_reset => true,
-		delay              => 0 ns
-	);
+		delay              => 0 ns);
 
 	constant number_of_interrupts:    positive := 8;
 	constant uart_baud:               positive := 115200;

top.vhd

@@ -319,7 +319,7 @@ begin
 
 	--- UART ----------------------------------------------------------
 	uart_fifo_0: work.uart_pkg.uart_top
-		generic map (g => g, baud => uart_baud, use_fifo => false)
+		generic map (g => g, baud => uart_baud, use_fifo => true)
 		port map (
 			clk => clk, 
 			rst => rst,