bios: implement comm_send.../receive..., minor fixes, add comm_echo t…

…ests

bios/comm/__comm_wait_timeout.s

@@ -0,0 +1,89 @@
+/**
+ * Copyright (c) 2023, 2024 Adrian "asie" Siekierka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+	.arch	i186
+	.code16
+	.intel_syntax noprefix
+
+#include "../common.inc"
+
+    // Input:
+    // - BH = awaited mask (any bit)
+    // - CX = timeout
+    // Output:
+    // - AH = 0 if success, 1 if timeout, 2 if overrun, 3 if cancel
+    // - AL = (serial status & BH)
+    // Clobber: AX
+    //
+    // TODO: Halt CPU while waiting for serial input.
+    // Note that the serial send/receive interrupts will loop
+    // indefinitely until the byte is sent/received.
+
+    .global __comm_wait_timeout
+__comm_wait_timeout:
+    pushf
+    push dx
+    sti
+
+    ss mov dx, [tick_count]
+    add dx, cx // DX = final tick count
+
+1:
+    xor ax, ax
+    in al, IO_SERIAL_STATUS
+    and al, bh
+    jnz 8f // received mask?
+
+    cmp cx, 0xFFFF
+    je 2f // skip timeout?
+
+    test cx, cx
+    jz 7f // zero timeout?
+    ss cmp dx, [tick_count]
+    jle 7f // timeout?
+
+2:
+    // check for cancel key
+    ss mov ax, [comm_cancel_key]
+    test ax, ax
+    jz 1b // cancel key not set?
+    ss and ax, [keys_held]
+    ss cmp ax, [comm_cancel_key]
+    jne 1b // cancel key combo not matched?
+
+    mov ah, 3 // return cancel
+    jmp 9f
+
+7:
+    mov ah, 1 // return timeout
+    jmp 9f
+
+8:
+    test al, SERIAL_OVERRUN
+    jz 9f // not overrun? (only checked if overrun in mask)
+    mov ah, 2 // return overrun
+
+9:
+    pop dx
+    popf
+    ret
+

bios/comm/comm.s

@@ -30,12 +30,12 @@
 irq_comm_handlers:
 	.word comm_open
 	.word comm_close
-	.word error_handle_irq20 // TODO: comm_send_char
-	.word error_handle_irq20 // TODO: comm_receive_char
-	.word error_handle_irq20 // TODO: comm_receive_with_timeout
-	.word error_handle_irq20 // TODO: comm_send_string
-	.word error_handle_irq20 // TODO: comm_send_block
-	.word error_handle_irq20 // TODO: comm_receive_block
+	.word comm_send_char
+	.word comm_receive_char
+	.word comm_receive_with_timeout
+	.word comm_send_string
+	.word comm_send_block
+	.word comm_receive_block
 	.word comm_set_timeout
 	.word comm_set_baudrate
 	.word comm_get_baudrate
@@ -49,13 +49,13 @@ irq_comm_handler:
 	iret
 
 	.section ".data"
+	.global comm_baudrate
+comm_baudrate: .byte 1 // 38400 bps
 	.global comm_recv_timeout
 comm_recv_timeout: .word 0xFFFF
 	.global comm_send_timeout
 comm_send_timeout: .word 0xFFFF
 
 	.section ".bss"
-	.global comm_baudrate
-comm_baudrate: .byte 0
 	.global comm_cancel_key
 comm_cancel_key: .word 0

bios/comm/comm_receive_block.s

@@ -0,0 +1,68 @@
+/**
+ * Copyright (c) 2023, 2024 Adrian "asie" Siekierka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+	.arch	i186
+	.code16
+	.intel_syntax noprefix
+
+#include "../common.inc"
+
+/**
+ * INT 14h AH=07h - comm_receive_block
+ * Input:
+ * - CX = Length, in bytes
+ * - DS:DX = Input buffer
+ * Output:
+ * - AX = Status
+ * - DX = Number of bytes received
+ */
+    .global comm_receive_block
+comm_receive_block:
+    push cx
+    push di
+    push es
+    push ds
+    pop es
+    mov di, dx
+
+    // check for CX == 0
+    xor ax, ax
+    test cx, cx
+    jz 9f
+
+    mov dx, ax // DX = 0
+
+1:
+    call comm_receive_char
+    test ah, ah
+    jnz 9f // if error, return error
+
+    stosb // write received character
+    inc dx
+    loop 1b
+
+9:
+    pop es
+    pop di
+    pop cx
+    ret
+

bios/comm/comm_receive_char.s

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) 2023, 2024 Adrian "asie" Siekierka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+	.arch	i186
+	.code16
+	.intel_syntax noprefix
+
+#include "../common.inc"
+
+/**
+ * INT 14h AH=03h - comm_receive_char
+ * Input:
+ * Output:
+ * - AX = Character or status
+ */
+    .global comm_receive_char
+comm_receive_char:
+    push cx
+    ss mov cx, [comm_recv_timeout]
+    call comm_receive_with_timeout
+    pop cx
+    ret
+

bios/comm/comm_receive_with_timeout.s

@@ -0,0 +1,63 @@
+/**
+ * Copyright (c) 2023, 2024 Adrian "asie" Siekierka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+	.arch	i186
+	.code16
+	.intel_syntax noprefix
+
+#include "../common.inc"
+
+/**
+ * INT 14h AH=04h - comm_receive_with_timeout
+ * Input:
+ * - CX = Timeout, in frames
+ * Output:
+ * - AX = Character or status
+ */
+    .global comm_receive_with_timeout
+comm_receive_with_timeout:
+    push bx
+
+    // Clear overrun, in case it occured before.
+    in al, IO_SERIAL_STATUS
+    or al, SERIAL_OVERRUN_RESET
+    out IO_SERIAL_STATUS, al
+
+    mov bh, (SERIAL_OVERRUN | SERIAL_RX_READY)
+    call __comm_wait_timeout
+    test ah, ah
+    jnz 8f
+
+    // receive character
+    xor ax, ax
+    in al, IO_SERIAL_DATA
+    jmp 9f
+
+8:
+    // convert __comm_wait_timeout result to error code
+    xchg ah, al
+    mov ah, 0x81
+
+9:
+    pop bx
+    ret
+

bios/comm/comm_send_block.s

@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) 2023, 2024 Adrian "asie" Siekierka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+	.arch	i186
+	.code16
+	.intel_syntax noprefix
+
+#include "../common.inc"
+
+/**
+ * INT 14h AH=06h - comm_send_block
+ * Input:
+ * - CX = Length, in bytes
+ * - DS:DX = Input buffer
+ * Output:
+ * - AX = Status
+ */
+    .global comm_send_block
+comm_send_block:
+    push cx
+    push si
+    mov si, dx
+
+    // check for CX == 0
+    xor ax, ax
+    test cx, cx
+    jz 9f
+
+1:
+    lodsb
+    mov bl, al
+    call comm_send_char
+    test ax, ax
+    jnz 9f // if error, return error
+    loop 1b
+
+9:
+    pop si
+    pop cx
+    ret
+