diff options
| -rw-r--r-- | asm/asmlex.mll | 4 | ||||
| -rw-r--r-- | asm/assembler.ml | 8 | ||||
| -rw-r--r-- | cpu/cpu.ml | 1 | ||||
| -rw-r--r-- | cpu/os.asm | 103 |
4 files changed, 108 insertions, 8 deletions
diff --git a/asm/asmlex.mll b/asm/asmlex.mll index 7be493e..7459966 100644 --- a/asm/asmlex.mll +++ b/asm/asmlex.mll @@ -94,6 +94,10 @@ rule token = parse with Not_found -> ID id } | "0x" (((hexdigit)+) as n) { INT (read_16 n) } + | "'\\n'" { INT (Char.code '\n') } + | "'\\t'" { INT (Char.code '\t') } + | "'\\r'" { INT (Char.code '\r') } + | "'" (_ as c) "'" { INT (Char.code c) } | (digit)+ as n { INT (int_of_string n) } | "0b" (['0' '1']+ as n) { INT (read_2 n) } | ['A'-'Z']+ as name { try REG (List.assoc name regs) with Not_found -> raise (Asm_error ("no reg " ^ name))} diff --git a/asm/assembler.ml b/asm/assembler.ml index 66999fb..8c8ff97 100644 --- a/asm/assembler.ml +++ b/asm/assembler.ml @@ -2,6 +2,8 @@ open Asm open Printf open Lexing +exception No_such_label of string + let init_string n f = let res = String.make n 'a' in for i = 0 to n - 1 do res.[i] <- f i done; res @@ -83,13 +85,13 @@ let print_program p = let pc = ref 0 in let value = function | Imm i -> i - | Lab l -> fst (Imap.find l p.lbls) in + | Lab l -> try fst (Imap.find l p.lbls) with Not_found -> raise (No_such_label l) in let value2 = function | Imm i -> i - | Lab l -> fst (Imap.find l p.lbls) - !pc in + | Lab l -> try fst (Imap.find l p.lbls) - !pc with Not_found -> raise (No_such_label l) in let value3 = function | Imm i -> i - | Lab l -> (byte 16 (fst (Imap.find l p.lbls))) lsr 8 in + | Lab l -> try (byte 16 (fst (Imap.find l p.lbls))) lsr 8 with Not_found -> raise (No_such_label l) in let get_reps = function | R (o,r1,r2,r3) -> r (code o) r1 r2 r3, sprintf "%s %s %s %s" (List.assoc o rev_keywords) (rts r1) (rts r2) (rts r3) @@ -56,6 +56,7 @@ let cpu_ram ra we wa d = let iser = nonnull 8 ser_in in let ser = mux iser ser ser_in in let ser_busy = nonnull 8 ser in + let ser_busy = mux read_ser ser_busy (const "0") in let read_data = save_ser_in_busy ser_busy ^. save_next_ser (mux read_ser ser (zeroes 8)) ^. @@ -1,15 +1,58 @@ +# CONVENTION: +# return value for functions : in register A +# arguments for functions : registers A, B, C, D +# all registers are caller-saved, except SP which is preserved by function calls + .text -init: + li A msghello + jal ser_out_msg + + push Z +main_loop: + # Process serial input + jal check_input + jz A end_process_input + jal run_cmd +end_process_input: + + # Process clock ticking + pop D li B _clock lw B 0(B) - jz B init add D D B push D + + jz B main_loop li A msgtick jal ser_out_msg - pop D - j init + j main_loop + +# PROCEDURE: run_cmd +# ROLE: execute and clear command stored in cmdline +# ARGUMENTS: none +run_cmd: + push RA + + li A prompt + jal ser_out_msg + li A cmdline + jal ser_out_msg + li A endl + jal ser_out_msg + + li A error + jal ser_out_msg + li A cmdline_used + sw Z 0(A) + + pop RA + jr RA + + +# PROCEDURE: ser_out_msg +# ROLE: write null-terminated string to serial output +# ARGUMENTS: address of string in register A ser_out_msg: li C _output ser_out_msg_loop: @@ -21,5 +64,55 @@ ser_out_msg_loop: ser_out_msg_ret: jr RA +# PROCEDURE: check_input +# ROLE: check if an input byte is available. if it is, and is different from '\n' (10), add it to cmdline +# ARGUMENTS: none +# RETURN VALUE: 1 if read byte was '\n', 0 otherwise +# WARNING: no buffer overflow check. +check_input: + li A _input + lb A 0(A) + jz A check_input_ret + move B A + sei A A '\n' + jz A add_b_to_string + move B Z +add_b_to_string: + push A + li A cmdline + li D cmdline_used + lw C 0(D) + add A A C + sb B 0(A) + incri C 1 + sw C 0(D) + pop A +check_input_ret: + jr RA + + +# READ-ONLY PROGRAM DATA +msghello: + ascii "Hello, world!\n" msgtick: - ascii "Tick!" + ascii " ..." +prompt: + ascii "\n$ " +endl: + ascii "\n" +error: + ascii "Sorry but I'm to stupid to understand that.\n" + + +.data +# Space where command-line is buffered from serial input +cmdline: + byte 256 +# Number of bytes used in the command-line buffer +cmdline_used: + word 1 + + + + + |