diff options
Diffstat (limited to 'cpu/os.asm')
| -rw-r--r-- | cpu/os.asm | 61 |
1 files changed, 33 insertions, 28 deletions
@@ -1,21 +1,26 @@ # 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 +# 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 +# Labels beginning with '_' are not meant to be used outside of the function where +# they are declared. .text + +# PROCEDURE: main loop +# ROLE: starts with the CPU then runs continuously jal run_unit_tests li A msghello jal ser_out_msg push Z -main_loop: +_main_loop: # Process serial input jal check_input - jz A end_process_input + jz A _end_process_input jal run_cmd -end_process_input: +_end_process_input: # Process clock ticking pop D @@ -24,10 +29,10 @@ end_process_input: add D D B push D - jz B main_loop + jz B _main_loop li A msgtick jal ser_out_msg - j main_loop + j _main_loop # PROCEDURE: run_cmd # ROLE: execute and clear command stored in cmdline @@ -57,13 +62,13 @@ run_cmd: # ARGUMENTS: address of string in register A ser_out_msg: li C _output -ser_out_msg_loop: +_ser_out_msg_loop: lb B 0(A) - jz B ser_out_msg_ret + jz B _ser_out_msg_ret sb B 0(C) incri A 1 - j ser_out_msg_loop -ser_out_msg_ret: + j _ser_out_msg_loop +_ser_out_msg_ret: jr RA # PROCEDURE: check_input @@ -74,12 +79,12 @@ ser_out_msg_ret: check_input: li A _input lb A 0(A) - jz A check_input_ret + jz A _check_input_ret move B A sei A A '\n' - jz A add_b_to_string + jz A _ci_add_b_to_string move B Z -add_b_to_string: +_ci_add_b_to_string: push A li A cmdline li D cmdline_used @@ -90,7 +95,7 @@ add_b_to_string: sw C 0(D) pop A jz A check_input -check_input_ret: +_check_input_ret: jr RA # PROCEDURE: run_unit_tests @@ -104,11 +109,11 @@ run_unit_tests: move B Z -unit_test_begin: +_unit_test_begin: li D testlist add D D B lw D 0(D) - jz D unit_tests_done + jz D _unit_tests_done push B push D @@ -119,16 +124,16 @@ unit_test_begin: pop D jalr D li A testfail - jz B unit_test_failed + jz B _unit_test_failed li A testok -unit_test_failed: +_unit_test_failed: jal ser_out_msg pop B addi B B 2 - j unit_test_begin + j _unit_test_begin -unit_tests_done: +_unit_tests_done: pop RA jr RA @@ -235,21 +240,21 @@ testok: testfail: ascii "FAIL\n" test0: - ascii "Addition/substraction..........." + ascii "Addition/substraction.......... " test1: - ascii "Unsigned multiplication........." + ascii "Unsigned multiplication........ " test2: - ascii "Unsigned division..............." + ascii "Unsigned division.............. " test3: - ascii "Signed multiplication/division.." + ascii "Signed multiplication/division. " .data -# Space where command-line is buffered from serial input +# Space where command-line is buffered from serial input (256 bytes) cmdline: byte 256 -# Number of bytes used in the command-line buffer +# Number of bytes used in the command-line buffer (1 word) cmdline_used: word 1 |