penguin86/pato-z80-home-computer
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Trying to obtain fixed position system calls. Not working ATM

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This commit is contained in:
Daniele Verducci su MatissePenguin 2020-12-29 23:28:30 +01:00
parent c21462e52f
commit b1f9788772
6 changed files with 105 additions and 87 deletions
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3
assembly/applications/call_printc.asm Normal file
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@ -0,0 +1,3 @@
ld bc, 0xA000
call 0x0010
jp 0

4
assembly/bios/Makefile
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@ -1,6 +1,8 @@
bios:
@echo "Building PAT80 rom..."
@z80asm -i main.asm -o rom.bin
@z80asm -i main.asm -o rom.bin || (exit 1)
@echo "Generating label lookup table..."
@z80asm -i main.asm -o rom.bin -L 2>&1 | grep "Sys_" > rom.label
@echo "PAT80 Rom size:"
@du -h rom.bin
@echo "Stretching rom to EEPROM size..."

4
assembly/bios/libs/time.asm
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@ -12,9 +12,9 @@ Time_delay55:
bit 0,a ; 8
bit 0,a ; 8
bit 0,a ; 8
and a,255 ; 7
and 255 ; 7
dec bc ; 6
ld a,c ; 4
or a,b ; 4
or b ; 4
jp nz,Time_delay55 ; 10, total = 55 states/iteration
ret

72
assembly/bios/main.asm
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@ -19,6 +19,45 @@ jp Sysinit ; Startup vector: DO NOT MOVE! Must be the first instruction
; I/O 6 (0xC0 - 0xDF)
; I/O 7 (0xE0 - 0xFF)
; **** SYSTEM CALLS ****
; System calls provide access to low level functions (input from keyboard, output to screen etc).
; The name starts always with Sys_
; Prints string
; @param BC Pointer to a null-terminated string first character
org 0x0010
Sys_Print:
call Term_print
ret
; Writes a single character
; @param A Value of character to print
org 0x0020
Sys_Printc:
call Term_printc
ret
; Reads a single character
; @return A The read character
org 0x0030
Sys_Readc:
call Term_readc
ret
; Reads a line
; @return BC The pointer to a null-terminated read string
org 0x0040
Sys_Readline:
call Term_readline
ret
; Emits system beep
org 0x0050
Sys_Beep:
call Snd_beep
ret
; MEMORY CONFIGURATION
SYS_VAR_SPACE: EQU 0x8000
@ -49,37 +88,6 @@ include 'libs/time.asm'
;include 'tests/sndtest.asm'
; **** SYSTEM CALLS ****
; Prints string
; @param BC Pointer to a null-terminated string first character
Print:
call Term_print
ret
; Writes a single character
; @param A Value of character to print
Printc:
call Term_printc
ret
; Reads a single character
; @return A The read character
Readc:
call Term_readc
ret
; Reads a line
; @return BC The pointer to a null-terminated read string
Readline:
call Term_readline
ret
; Emits system beep
Beep:
call Snd_beep
ret
; **** SYSTEM INITIALIZATION ****
Sysinit:
; Init snd driver
@ -93,7 +101,7 @@ Sysinit:
call Time_delay55
; Play startup sound
call Beep
call Sys_Beep
; Run memory monitor
call Monitor_main

104
assembly/bios/monitor.asm
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@ -32,18 +32,18 @@ MON_DUMP_BYTES_PER_LINE: EQU 8
Monitor_main:
; Print welcome string
ld bc, MON_WELCOME
call Print
call Sys_Print
monitor_main_loop:
; Newline
ld a, 10
call Printc
call Sys_Printc
; Draw prompt char
ld a, 62 ; >
call Printc
call Sys_Printc
; Read char from command line
call Readc ; blocking: returns when a character was read and placed in A reg
call Sys_Readc ; blocking: returns when a character was read and placed in A reg
call Strings_charToUpper ; user may enter lowercase char: transform to upper
call Printc ; Print back the character to provide user feedback
call Sys_Printc ; Print back the character to provide user feedback
; Switch case
ld hl, MON_COMMAND_HELP
cp (hl) ; check incoming char is equal to command's first char
@ -68,27 +68,27 @@ Monitor_main:
jp z, monitor_adb
; Unrecognized command: print error and beep
ld bc, MON_ERR_SYNTAX
call Print
call Beep
call Sys_Print
call Sys_Beep
jp monitor_main_loop
monitor_help:
ld bc, MON_COMMAND_HELP + 1 ; autocomplete command
call Print
call Sys_Print
ld bc, MON_HELP
call Print
call Sys_Print
jp monitor_main_loop
; 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:
ld bc, MON_COMMAND_DUMP + 1 ; autocomplete command
call Print
call Sys_Print
; Now read the address from the user
call monitor_arg_2byte ; returns the read bytes in hl
ld a, 10 ; newline
call Printc
call Sys_Printc
; now start displaying bytes from memory
ld e, MON_DUMP_BYTES_LINES ; the number of lines to display
monitor_dump_show_bytes_loop:
@ -100,10 +100,10 @@ monitor_dump:
call monitor_printHexByte
; print four spaces
ld a, 32
call Printc
call Printc
call Printc
call Printc
call Sys_Printc
call Sys_Printc
call Sys_Printc
call Sys_Printc
monitor_dump_show_bytes_line_loop: ; counts down from 15 to 0
ld a, d
sub MON_DUMP_BYTES_PER_LINE + 1
@ -114,14 +114,14 @@ monitor_dump:
call monitor_printHexByte
; print space
ld a, 32
call Printc
call Sys_Printc
; if position is 4, print a second space (to group nibbles)
ld a, d
cp MON_DUMP_BYTES_PER_LINE / 2 + MON_DUMP_BYTES_PER_LINE + 1
jp nz, no_second_space
; print second space
ld a, 32
call Printc
call Sys_Printc
no_second_space:
; move to next mem position
inc hl
@ -139,23 +139,23 @@ monitor_dump:
sbc hl, bc
; print 3 spaces to separate hex from ascii
ld a, 32
call Printc
call Printc
call Printc
call Sys_Printc
call Sys_Printc
call Sys_Printc
no_mempos_decr:
; print ascii
ld a, (hl)
call monitor_printAsciiByte
; print space
ld a, 32
call Printc
call Sys_Printc
; if position is 12 (8+4), print a second space (to group nibbles)
ld a, d
cp MON_DUMP_BYTES_PER_LINE / 2 + 1
jp nz, no_second_space2
; print second space
ld a, 32
call Printc
call Sys_Printc
no_second_space2:
; move to next mem position
inc hl
@ -164,7 +164,7 @@ monitor_dump:
jp nz, monitor_dump_show_bytes_line_loop
; print newline
ld a, 10
call Printc
call Sys_Printc
; decrement line counter
dec e
jp nz, monitor_dump_show_bytes_loop ; if line counter is not 0, print another line
@ -175,13 +175,13 @@ monitor_dump:
; @uses a, b, c, h, l
monitor_set:
ld bc, MON_COMMAND_SET + 1 ; autocomplete command
call Print
call Sys_Print
; Now read the memory address to be changed from the user
call monitor_arg_2byte ; returns the read bytes in hl
; Start looping memory addresses
monitor_set_byte_loop:
ld a, 10 ; newline
call Printc
call Sys_Printc
; Print current address
ld a, h
call monitor_printHexByte
@ -189,21 +189,21 @@ monitor_set:
call monitor_printHexByte
; print two spaces
ld a, 32
call Printc
call Printc
call Sys_Printc
call Sys_Printc
; print previous memory content (hex)
ld a, (hl)
call monitor_printHexByte
; print two spaces
ld a, 32
call Printc
call Printc
call Sys_Printc
call Sys_Printc
; print previous memory content (ascii)
ld a, (hl)
call monitor_printAsciiByte
; print space
ld a, 32
call Printc
call Sys_Printc
; ask the user the new memory content
call monitor_arg_byte ; returns the read byte in a, exit code in b
; find if user pressed Q/ENTER
@ -217,8 +217,8 @@ monitor_set:
; user didn't press Q/ENTER: he inserted a valid byte
; print two spaces
ld a, 32
call Printc
call Printc
call Sys_Printc
call Sys_Printc
ld a, c ; restore valid byte in a
call monitor_printAsciiByte ; print user-inserted byte in ascii
ld a, c ; restore valid byte in a
@ -231,7 +231,7 @@ monitor_set:
; @uses a, b, c, h, l
monitor_zero: ; TODO: bugged, doesn't exit cycle
ld bc, MON_COMMAND_ZERO + 1 ; autocomplete command
call Print
call Sys_Print
; Now read the starting memory address
call monitor_arg_2byte ; returns the read bytes in hl
; starting addr in bc
@ -256,26 +256,26 @@ monitor_zero: ; TODO: bugged, doesn't exit cycle
monitor_load:
ld bc, MON_COMMAND_LOAD + 1 ; autocomplete command
call Print
call Sys_Print
jp monitor_main_loop
monitor_run:
ld bc, MON_COMMAND_RUN + 1 ; autocomplete command
call Print
call Sys_Print
; Now read the memory address to be changed from the user
call monitor_arg_2byte ; returns the read bytes in hl
ld a, 10 ; newline
call Printc
call Sys_Printc
jp (hl) ; Start executing code
monitor_adb:
ld bc, MON_COMMAND_ADB + 1 ; autocomplete command
call Print
call Sys_Print
; start copying incoming data to application space
call monitor_copyTermToAppMem
;jp APP_SPACE ; Start executing code
ld bc, APP_SPACE
call Print
call Sys_Print
jp monitor_main_loop
; Prints "0x" and read 1 hex byte (2 hex digits, e.g. 0x8C)
@ -285,7 +285,7 @@ monitor_adb:
monitor_arg_byte:
; Print 0x... prompt
ld bc, MON_ARG_HEX
call Print
call Sys_Print
; Read 2 digits
call monitor_arg_byte_impl
ret
@ -297,7 +297,7 @@ monitor_arg_byte:
monitor_arg_2byte:
; Print 0x... prompt
ld bc, MON_ARG_HEX
call Print
call Sys_Print
; Read 2 digits
call monitor_arg_byte_impl
ld h, a ; move result to h
@ -348,7 +348,7 @@ monitor_arg_byte_impl:
; (0 if no control key was, pressed, 1 for Q, 2 for RETURN)
; @uses a, b
monitor_readHexDigit:
call Readc
call Sys_Readc
; check if user pressed Q
; if user pressed Q, return exit code 1 in b and 0 in a
cp 81
@ -372,7 +372,7 @@ monitor_readHexDigit:
jp p, monitor_readHexDigit_char ; if not negative (ns), maybe is a char
; otherwise is a number! First print for visive feedback
ld a, b
call Printc
call Sys_Printc
; then convert to its value subtracting 48
sub a, 48
ld b, 0 ; set b to exit code 0 to represent "valid value in a"
@ -384,7 +384,7 @@ monitor_readHexDigit:
jp m, monitor_readHexDigit ; if negative (s), ascii code is under 65: ignore char
; otherwise is a valid char (A-F). Print for visive feedback
ld a, b
call Printc
call Sys_Printc
; Its numeric value is 10 (A) to 15 (F). To obtain this, subtract 55.
sub a, 55
ld b, 0 ; set b to exit code 0 to represent "valid value in a"
@ -407,10 +407,10 @@ monitor_printHexByte:
ld c, a
; rotate out the least significant nibble to obtain a byte with the most significant nibble
; in the least significant nibble position
rrca a
rrca a
rrca a
rrca a
rrca
rrca
rrca
rrca
; the upper nibble must now be discarded
and %00001111
call monitor_printHexDigit
@ -436,14 +436,14 @@ monitor_printHexDigit:
ld a, b ; restore a
; add 48 (the ASCII number for 0) to obtain the corresponding number
add 48
call Printc
call Sys_Printc
ret
monitor_printHexDigit_letter:
ld a, b ; restore a
; to obtain the corresponding letter we should subtract 10 (so we count from A)
; and add 65 (the ASCII number for A). So -10+65=+55 we add only 55.
add 55
call Printc
call Sys_Printc
ret
; Prints an ASCII character. Similar to system Print function, but
@ -462,11 +462,11 @@ monitor_printAsciiByte:
jp p, monitor_printAsciiByte_nonprintable
; otherwise is a printable ascii char
ld a, b ; restore a
call Printc
call Sys_Printc
ret
monitor_printAsciiByte_nonprintable:
ld a, 46 ; print dot
call Printc
call Sys_Printc
ret
; Copy data from STDIN to application memory. This is tought to be used with parallel terminal, not keyboard:
@ -476,7 +476,7 @@ monitor_copyTermToAppMem:
ld b, 255; MON_ADB_TIMEOUT ; the timeout counter (number cycles without available data that represent the end of stream)
monitor_copyTermToAppMem_loop:
dec b ; decrement the timeout counter
ret 0 ; if counter is 0, timeout reached: return
ret z ; if counter is 0, timeout reached: return
; check if bytes are available
call Term_availb
cp 0

5
assembly/bios/rom.label Normal file
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@ -0,0 +1,5 @@
Sys_Beep: equ $0050
Sys_Print: equ $0010
Sys_Printc: equ $0020
Sys_Readc: equ $0030
Sys_Readline: equ $0040