From 3ebf35fa77a7ca336c24df1584d6c483c3b7fb67 Mon Sep 17 00:00:00 2001 From: "Daniele Verducci (ZenPenguin)" Date: Sat, 2 Jan 2021 10:53:30 +0100 Subject: [PATCH] WIP immediate return to monitor via interrupt --- assembly/os/abi-generated.asm | 12 ++++---- assembly/os/main.asm | 18 ++++++++++-- assembly/os/monitor.asm | 52 +++++++++++++++++++++++++++++++++-- 3 files changed, 71 insertions(+), 11 deletions(-) diff --git a/assembly/os/abi-generated.asm b/assembly/os/abi-generated.asm index 97e3aa5..675f2f2 100644 --- a/assembly/os/abi-generated.asm +++ b/assembly/os/abi-generated.asm @@ -1,6 +1,6 @@ -Sys_ABI: equ $0003 -Sys_Beep: equ $0013 -Sys_Print: equ $0007 -Sys_Printc: equ $000a -Sys_Readc: equ $000d -Sys_Readline: equ $0010 +Sys_ABI: equ $007e +Sys_Beep: equ $008e +Sys_Print: equ $0082 +Sys_Printc: equ $0085 +Sys_Readc: equ $0088 +Sys_Readline: equ $008b diff --git a/assembly/os/main.asm b/assembly/os/main.asm index d43f86e..5fd4148 100644 --- a/assembly/os/main.asm +++ b/assembly/os/main.asm @@ -19,9 +19,16 @@ jp Sysinit ; Startup vector: DO NOT MOVE! Must be the first instruction ; 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) @@ -101,7 +108,12 @@ Sysinit: ; Play startup sound call Sys_Beep - ; Run memory monitor - call Monitor_main + ; 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 - halt + ; User exited from memory monitor without loading a program. Do nothing. + mloop: + ; Main loop: do nothing. + jp mloop diff --git a/assembly/os/monitor.asm b/assembly/os/monitor.asm index 0037f42..f854988 100644 --- a/assembly/os/monitor.asm +++ b/assembly/os/monitor.asm @@ -21,8 +21,9 @@ MON_COMMAND_ZERO: DB "ZERO",0 MON_COMMAND_LOAD: DB "LOAD",0 MON_COMMAND_RUN: DB "RUN",0 MON_COMMAND_ADB: DB "ADB",0 +MON_COMMAND_QUIT: DB "QUIT",0 MON_ARG_HEX: DB " 0x",0 -MON_HELP: DB 10,"Available commands:\nHELP prints this message\nDUMP [ADDR] shows memory content\nSET [ADDR] sets memory content\nZERO [ADDR] [ADDR] sets all bytes to 0 in the specified range\nLOAD\nRUN [ADDR] executes code starting from ADDR\nADB starts Assembly Deploy Bridge",0 +MON_HELP: DB 10,"Available commands:\nHELP prints this message\nDUMP [ADDR] shows memory content\nSET [ADDR] sets memory content\nZERO [ADDR] [ADDR] sets all bytes to 0 in the specified range\nLOAD\nRUN [ADDR] executes code starting from ADDR\nADB starts Assembly Deploy Bridge\nQUIT exits",0 MON_MSG_ADB: DB 10,"Waiting for data.",0 MON_ERR_SYNTAX: DB " Syntax error",0 ;MON_ADB_TIMEOUT: EQU 0xFF // Number of cycles after an ADB binary transfer is considered completed @@ -30,6 +31,8 @@ MON_DUMP_BYTES_LINES: EQU 8 MON_DUMP_BYTES_PER_LINE: EQU 8 Monitor_main: + ; Disable maskable interrupts. MI are used to break a program execution and bring up immediately the memory monitor. + call monitor_disable_int ; Print welcome string ld bc, MON_WELCOME call Sys_Print @@ -66,6 +69,9 @@ Monitor_main: ld hl, MON_COMMAND_ADB cp (hl) jp z, monitor_adb + ld hl, MON_COMMAND_QUIT + cp (hl) + jp z, monitor_quit ; Unrecognized command: print error and beep ld bc, MON_ERR_SYNTAX call Sys_Print @@ -80,6 +86,17 @@ monitor_help: call Sys_Print jp monitor_main_loop +monitor_quit: + ld bc, MON_COMMAND_QUIT + 1 ; autocomplete command + call Sys_Print + ; newline + ld a, 10 + call Sys_Printc + ; re-enable interrupts + call monitor_enable_int + reti ; return from interrupt + + ; Asks the user for a memory position and shows the following 64 bytes of memory ; @uses a, b, c, d, e, h, l monitor_dump: @@ -257,6 +274,7 @@ monitor_zero: ; TODO: bugged, doesn't exit cycle monitor_load: ld bc, MON_COMMAND_LOAD + 1 ; autocomplete command call Sys_Print + ; TODO: When implemented, re-enable interrupts before run application jp monitor_main_loop monitor_run: @@ -266,14 +284,20 @@ monitor_run: call monitor_arg_2byte ; returns the read bytes in hl ld a, 10 ; newline call Sys_Printc - jp (hl) ; Start executing code + ld sp, hl ; Point stack pointer to code to execute + ; re-enable interrupts + call monitor_enable_int + reti monitor_adb: ld bc, MON_COMMAND_ADB + 1 ; autocomplete command call Sys_Print ; start copying incoming data to application space call monitor_copyTermToAppMem + ; call monitor_enable_int ; re-enable interrupts ;jp APP_SPACE ; Start executing code + + ; ld bc, APP_SPACE ; call Sys_Print jp monitor_main_loop @@ -516,4 +540,28 @@ monitor_copyTermToAppMem: dec d jp monitor_copyTermToAppMem_loop ; continue loop +; Restores registers and re-enables interrupt. +; Enable interrupts: when the BREAK key is pressed, a maskable interrupt is generated and +; the CPU jumps to 0x38 reset vector, where if finds a call to Memory monitor (see main.asm). +; In this way, BREAK key brings up memory monitor at any time. +; To be called before the user exits from monitor +monitor_enable_int: + ; exchange registers + exx + ex af, af' + ; enable interrupts + ei + im 1 ; set interrupt mode 1 (on interrupt jumps to 0x38) + ret + +; Saves registers and disables interrupts. +; To be called when the monitor starts +monitor_disable_int: + di ; disable interrupt + ; exchange registers + exx + ex af, af' + ret + +