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diff --git a/tools/spasm/readme.txt b/tools/spasm/readme.txt new file mode 100644 index 0000000..8baa290 --- /dev/null +++ b/tools/spasm/readme.txt @@ -0,0 +1,120 @@ +nv-SPASM 0.34.1 +(c) 2014-2015 Giuseppe Gatta, a.k.a. nextvolume <tails92@gmail.com> +------------------------- + +1. What is this? +2. Features +3. How to use +4. License + +1. What is this? +-------------------------- + +nv-SPASM is a stand-alone MIPS assembler that can output either a little-endian flat binary file +or Sony PlayStation PS-X EXE executable (the default). + +It is simple and lightweight, and it is ideal for people who just want to play around +with assembly without bothering with too many details which would arise with +more advanced tools, such as those provided by the GNU project. + +nv-SPASM is also meant to be compatible with the Hitmen group's SPASM assembler, +which was an early tool for PlayStation homebrew programmers who had no access +to more advanced software development kits, such as Net Yaroze or PsyQ. + +While to most a tool like SPASM isn't as useful as it was back in the day, due to the +availability of freely usable software development kits like the PSXSDK, as already +mentioned before there are still some use cases for which it's more feasible +to use nv-SPASM instead of more advanced tools. + +And, why not? nv-SPASM is easier to hack and to learn from than more advanced, +complex designs. + +You could use it as the assembler for your virtual machine, or even embed this assembler inside it. + +1. What is this not? +-------------------------- + +nv-SPASM isn't a complex and full-fledged macro assembler; in fact it does not +even support macros currently. + +You can't easily mix code written in a high-level language with assembly code +with nv-SPASM, as nv-SPASM is unable to output object files that can be linked +against other object files. + +nv-SPASM does not currently support complex expressions, just very simple ones. + +2. Features +-------------------------- + +- Complete MIPS R3000 instruction set support, with the following pseudo-instructions + implemented: + + - B - unconditional branch + - LA, LI - load label/integer inside a register (LA and LI are the same thing in nv-SPASM) + - NOP - No operation + - MOVE - Copy the contents of a register into another + - SUBI - Subtract immediate from register + - SUBIU - Subtract immediate unsigned from register + - BEQZ - Branch if register is Equal to Zero + - BNEZ - Branch if register is Not Equal to Zero + - BAL - unconditional branch-and-link + - ORG - move start address to the desired address + it relocates every instruction, and must be the first instruction. + - INCLUDE - include a source file + - INCBIN - include a binary file + - DCB - declare a block of bytes + - DB - declare bytes and/or strings + - DH - declare half-words and/or strings + - DW - declare words and/or strings + - ALIGN - align incoming code to the specified boundary + +- Compatibility with the Hitmen group's SPASM assembler and thus the possibility + of assembling software developed with it, barring bugs in nv-SPASM or the fact + that the original source code may depend on bugs in the Hitmen's SPASM assembler + in order to assemble correctly. + +- Very simple expression support, single operator, two operands. + For laymen, this means that while for instance 3+3 is rendered as 6, + 3+3+2 is rendered as 5, as if it were 3+2. + This is coherent with the original SPASM assembler. + Supported operators are +, -, >>, <<, & and | + +- Automatic generation of Sony PlayStation PS-X EXE executables. + +- Symbol names (labels) can be treated just like normal numerical values, + the numerical value being either the program counter value at the moment + the label was met by the assembler, or a value set with an EQU or = statement. + + +3. How to use +-------------------------- + +nv-SPASM is really simple to use, and does not need any special explanation. +Therefore, it will suffice to report its usage banner. + +nv-spASM version 0.34.1 (c) 2014-2015 nextvolume +Assembler for the Sony PlayStation + +Usage: ./spasm [options] infile outfile + +Options: -b create binary file instead of PS-X EXE + -N do not pad executable + -S be case sensitive on file paths + +4. License +-------------------------- + +It is permitted to do (almost) anything with the nv-SPASM code and documentation. +The only restriction is that all existing copyright notices must remain intact, and +modifed versions must ship with the corresponding modified source code. + +fcaseopen.c is (C) 2009 Keith Bauer. Read fcaseopen.c for the license (BSD-style) + +5. Useful information +-------------------------- + +Hitmen's official website <http://www.hitmen-console.org> +- The README file for Hitmen's original SPASM assembler is a good read, + as this assembler tries to closely follow it. +- The GreenTro source code is another good resource, as it was developed with SPASM, + and thus it can be considered an example to write nv-SPASM assembly source code. |