# Debug the basic usage
Next, talk about the basic usage of debug
| debug basic instructions | Full instruction name | usage | use |
|---|---|---|---|
| ？ | ---------- | ? | Show debug command list |
| A | assemble | A [ address ] | The input source program is compiled into object code and instruction stored starting from the specified address location. If the defaulted start address, from the current CS: 100 start address is stored. A command line by the assembler, the main procedures for assembling small pieces or modification of the target program |
| C | compare | C range address | Comparison of the two parts of memory |
| D | dump | D [ range ] | Display part of the memory contents |
| E | enter | E address [ list ] | Starting at the specified address, data input |
| F | fill | F range list | Section of memory is filled with the specified value |
| G | go | G [ = address ] [ addresses ] | Running in memory executable file |
| H | hex | H value1 value2 | Hexadecimal arithmetic execution |
| I | input | I port | Display 1-byte value from a specific port |
| L | load | L [ address ] [driver ] [ firstsector ] [ number ] | The file or disk sector content is loaded into memory |
| M | move | M range address | Copy the contents of the memory block |
| N | name | N [pathname] [guile] | Parameter name of the executable file Debug l (load) or w (write) command, or specify the executable file is being debugged |
| THE | output | O port byte | Value output port to send a byte |
| P | proceed | P [ =address ] [ number ] | Execution cycle, repeated string instructions, or software interrupt subroutine; or by any other instruction trace |
| Q | quit | Q | Exit debug session without saving the current test file |
| R | register | R [ register ] | When the register name is given, then the display memory register can be modified. Default register names, the contents of all registers and the current value (not modified) is displayed |
| S | search | S range list | Search pattern of one or more byte values in the memory section |
| T | trace | T [ =address] [ value ] | Execute one instruction, then displays the contents of all registers, the instruction decoded form of the status of all flags to be executed next, and Debug |
| The | unassemble | U [ range ] | Disassemble bytes and displays the corresponding original sentence |
| W | write | W [address ] [ drive ] [ firstsector ] [ number ] | The test file is written to disk |
| FAR | allocate expanded memory | XA [ # pages ] | Allocate extended memory |
| XD | deallocate expanded memory | XD [ handle ] | The release of extended memory |
| XM | map expanded memory pages | XM [ Lpage ] [ Ppage ] [ handle ] | Expanded memory page mapping |
| XS | display expanded memory status | XS | Displays the status of extended memory |
The above is debug profile.
Learn assembly language and call the debug time, mainly used to -L -U -D -G -T -P command
-L -G run into the disassembly -T -U single step (you can enter the subroutine) -P single step (do not enter the subroutine) -D query memory
Assembly language program establishes steps:
- edit establish the source file formats: edit xxx.asm (asm must file name extension, or can not use masm call), generate obj file.
- masm generating link file: masm xxx.asm then generates obj file obj connection file is the file, the next link required link file generated exe
- exe format generating link: link xxx.obj generate executable exe