Merge branch 'master' into monitor-interrupt

2021-01-03 08:23:56 +01:00
parent 3ebf35fa77 00b6c76e18
commit b98ad3e136
37 changed files with 454 additions and 1 deletions
--- a/pat80-computer/software/z80-assembly/os/main.asm
+++ b/pat80-computer/software/z80-assembly/os/main.asm
@ -0,0 +1,125 @@
+jp Sysinit     ; Startup vector: DO NOT MOVE! Must be the first instruction
+
+; Pat80 BIOS v0.01
+; @author: Daniele Verducci
+;
+; MEMORY MAP
+;   ROM is at 0x0000
+;   RAM is at 0x8000
+;       SYSTEM VAR SPACE: 0x8000 - 0x8FFF (4kb)
+;       DRIVERS VAR SPACE: 0x9000 - 0x9FFF (4kb)
+;       APPLICATION VAR SPACE: 0xA000 - 0xFFFF (24kb)
+; I/O MAP
+;   I/O 0 (0x00 - 0x1F) Parallel terminal (uses addr 0x00 only)
+;   I/O 1 (0x20 - 0x3F) Sound card (uses addr 0x20 only)
+;   I/O 2 (0x40 - 0x5F)
+;   I/O 3 (0x60 - 0x7F)
+;   I/O 4 (0x80 - 0x9F)
+;   I/O 5 (0xA0 - 0xBF)
+;   I/O 6 (0xC0 - 0xDF)
+;   I/O 7 (0xE0 - 0xFF)
+
+; **** RESET/INTERRUPT VECTOR ****
+
+; Maskable interrupt mode 1: execute memory monitor
+ds 0x38
+call Monitor_main
+
+; **** SYSTEM CALLS ****
+; System calls provide access to low level functions (input from keyboard, output to screen etc).
+; The name starts always with Sys_
+ds 0x40	; Place system calls after Z80 reset/interrupt subroutines space
+
+; Returns ABI version.
+; (ABI -> https://en.wikipedia.org/wiki/Application_binary_interface)
+; Any Pat80 application should check the ABI version on startup, and refuse to run if not compatible.
+; @return bc the ABI version
+Sys_ABI:
+    ld bc, 0
+    ret
+
+; Prints string
+; @param BC Pointer to a null-terminated string first character
+Sys_Print:
+    jp Term_print
+
+; Writes a single character
+; @param A Value of character to print
+Sys_Printc:
+    jp Term_printc
+
+; Reads a single character
+; @return A The read character
+Sys_Readc:
+    jp Term_readc
+
+; Reads a line
+; @return BC The pointer to a null-terminated read string
+Sys_Readline:
+    jp Term_readline
+
+; Emits system beep
+Sys_Beep:
+    jp Snd_beep
+
+
+
+; MEMORY CONFIGURATION
+SYS_VAR_SPACE: EQU 0x8000
+DRV_VAR_SPACE: EQU 0x9000
+APP_SPACE: EQU 0xA000
+
+; SYSTEM CONFIGURATION
+IO_0: EQU 0x00
+IO_1: EQU 0x20
+IO_2: EQU 0x40
+IO_3: EQU 0x60
+IO_4: EQU 0x80
+IO_5: EQU 0xA0
+IO_6: EQU 0xC0
+IO_7: EQU 0xE0
+
+
+
+
+
+
+;include 'drivers/hd44780.asm'
+;include 'drivers/keyboard.asm'
+include 'drivers/arduino_terminal.asm'
+include 'drivers/sn76489.asm'
+include 'monitor.asm'
+include 'libs/time.asm'
+;include 'tests/sndtest.asm'
+
+
+; **** SYSTEM INITIALIZATION ****
+Sysinit:
+    ; Init snd driver
+    call Snd_init
+
+    ; Init video
+    ; TODO
+
+    ; Wait for audio amp to unmute
+    ld bc, TIME_DUR_SECOND
+    call Time_delay55
+
+    ; Play startup sound
+    call Sys_Beep
+
+	; Run memory monitor
+	ei ; enable maskabpe interrupts
+	im 1 ; set interrupt mode 1 (on interrupt jumps to 0x38)
+	rst 0x38 ; throw fake interrupt: jump to interrupt routine to start monitor
+
+	; User exited from memory monitor without loading a program. Do nothing.
+	mloop:
+		; Main loop: do nothing.
+		jp mloop
+
+    ; DEBUG: Echo chars
+    ; loop:
+    ;     call Term_readc
+    ;     call Term_printc
+    ;     jp loop