WIP immediate return to monitor via interrupt
This commit is contained in:
Daniele Verducci (ZenPenguin)
parent
1622fb2381
commit
3ebf35fa77
@ -1,6 +1,6 @@
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Sys_ABI: equ $0003
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Sys_Beep: equ $0013
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Sys_Print: equ $0007
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Sys_Printc: equ $000a
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Sys_Readc: equ $000d
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Sys_Readline: equ $0010
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Sys_ABI: equ $007e
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Sys_Beep: equ $008e
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Sys_Print: equ $0082
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Sys_Printc: equ $0085
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Sys_Readc: equ $0088
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Sys_Readline: equ $008b
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@ -19,9 +19,16 @@ jp Sysinit ; Startup vector: DO NOT MOVE! Must be the first instruction
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; I/O 6 (0xC0 - 0xDF)
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; I/O 7 (0xE0 - 0xFF)
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; **** RESET/INTERRUPT VECTOR ****
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; Maskable interrupt mode 1: execute memory monitor
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ds 0x38
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call Monitor_main
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; **** SYSTEM CALLS ****
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; System calls provide access to low level functions (input from keyboard, output to screen etc).
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; The name starts always with Sys_
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ds 0x40 ; Place system calls after Z80 reset/interrupt subroutines space
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; Returns ABI version.
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; (ABI -> https://en.wikipedia.org/wiki/Application_binary_interface)
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@ -101,7 +108,12 @@ Sysinit:
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; Play startup sound
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call Sys_Beep
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; Run memory monitor
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call Monitor_main
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; Run memory monitor
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ei ; enable maskabpe interrupts
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im 1 ; set interrupt mode 1 (on interrupt jumps to 0x38)
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rst 0x38 ; throw fake interrupt: jump to interrupt routine to start monitor
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halt
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; User exited from memory monitor without loading a program. Do nothing.
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mloop:
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; Main loop: do nothing.
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jp mloop
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@ -21,8 +21,9 @@ MON_COMMAND_ZERO: DB "ZERO",0
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MON_COMMAND_LOAD: DB "LOAD",0
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MON_COMMAND_RUN: DB "RUN",0
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MON_COMMAND_ADB: DB "ADB",0
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MON_COMMAND_QUIT: DB "QUIT",0
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MON_ARG_HEX: DB " 0x",0
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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
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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
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MON_MSG_ADB: DB 10,"Waiting for data.",0
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MON_ERR_SYNTAX: DB " Syntax error",0
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;MON_ADB_TIMEOUT: EQU 0xFF // Number of cycles after an ADB binary transfer is considered completed
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@ -30,6 +31,8 @@ MON_DUMP_BYTES_LINES: EQU 8
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MON_DUMP_BYTES_PER_LINE: EQU 8
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Monitor_main:
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; Disable maskable interrupts. MI are used to break a program execution and bring up immediately the memory monitor.
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call monitor_disable_int
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; Print welcome string
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ld bc, MON_WELCOME
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call Sys_Print
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@ -66,6 +69,9 @@ Monitor_main:
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ld hl, MON_COMMAND_ADB
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cp (hl)
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jp z, monitor_adb
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ld hl, MON_COMMAND_QUIT
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cp (hl)
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jp z, monitor_quit
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; Unrecognized command: print error and beep
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ld bc, MON_ERR_SYNTAX
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call Sys_Print
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@ -80,6 +86,17 @@ monitor_help:
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call Sys_Print
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jp monitor_main_loop
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monitor_quit:
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ld bc, MON_COMMAND_QUIT + 1 ; autocomplete command
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call Sys_Print
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; newline
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ld a, 10
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call Sys_Printc
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; re-enable interrupts
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call monitor_enable_int
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reti ; return from interrupt
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; Asks the user for a memory position and shows the following 64 bytes of memory
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; @uses a, b, c, d, e, h, l
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monitor_dump:
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@ -257,6 +274,7 @@ monitor_zero: ; TODO: bugged, doesn't exit cycle
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monitor_load:
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ld bc, MON_COMMAND_LOAD + 1 ; autocomplete command
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call Sys_Print
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; TODO: When implemented, re-enable interrupts before run application
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jp monitor_main_loop
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monitor_run:
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@ -266,14 +284,20 @@ monitor_run:
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call monitor_arg_2byte ; returns the read bytes in hl
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ld a, 10 ; newline
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call Sys_Printc
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jp (hl) ; Start executing code
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ld sp, hl ; Point stack pointer to code to execute
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; re-enable interrupts
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call monitor_enable_int
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reti
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monitor_adb:
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ld bc, MON_COMMAND_ADB + 1 ; autocomplete command
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call Sys_Print
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; start copying incoming data to application space
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call monitor_copyTermToAppMem
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; call monitor_enable_int ; re-enable interrupts
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;jp APP_SPACE ; Start executing code
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; ld bc, APP_SPACE
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; call Sys_Print
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jp monitor_main_loop
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@ -516,4 +540,28 @@ monitor_copyTermToAppMem:
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dec d
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jp monitor_copyTermToAppMem_loop ; continue loop
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; Restores registers and re-enables interrupt.
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; Enable interrupts: when the BREAK key is pressed, a maskable interrupt is generated and
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; the CPU jumps to 0x38 reset vector, where if finds a call to Memory monitor (see main.asm).
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; In this way, BREAK key brings up memory monitor at any time.
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; To be called before the user exits from monitor
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monitor_enable_int:
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; exchange registers
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exx
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ex af, af'
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; enable interrupts
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ei
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im 1 ; set interrupt mode 1 (on interrupt jumps to 0x38)
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ret
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; Saves registers and disables interrupts.
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; To be called when the monitor starts
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monitor_disable_int:
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di ; disable interrupt
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; exchange registers
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exx
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ex af, af'
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ret
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