From cad06d86cd309074fffb5cce9d1f3b79b40f3891 Mon Sep 17 00:00:00 2001 From: jjsuperpower Date: Sun, 21 Aug 2022 22:33:56 -0500 Subject: basic alu coded and tested --- doc/ASAP32-ISA.md | 229 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 229 insertions(+) create mode 100644 doc/ASAP32-ISA.md (limited to 'doc/ASAP32-ISA.md') diff --git a/doc/ASAP32-ISA.md b/doc/ASAP32-ISA.md new file mode 100644 index 0000000..b5ed60d --- /dev/null +++ b/doc/ASAP32-ISA.md @@ -0,0 +1,229 @@ +# Vertex KISS 32 - Machine Code Spec +^ So Vertex is already a name for an FPGA, should we change this? +I propose a different name: + + ASAP Soc 32 a KISS inspired architecture + + As + Simple + As + Possible + +## General Instruction Format + X = HEX + B = BIN + + d = HEX (not used / don't care) + + MAX INSTRUCTIIONS = 256 + ALL INSTRUCTIONS ARE ATOMIC + + ALL MEMORY ADDRESSES ARE 32-bit, not 8-bit + ^ What do you think about this? 32 bits is usually and 'int' in C + This would extend the address space, kinda + + Also I have been reading about caching, I think the instruction width needs to be the same as the data memory + +### C-Type, Control + XX X X XXXX + Opcode d RS1 IMM + +### I-Type, Immediate + XX X X XXXX + Opcode RD RS1 IMM + +### R-Type, Arithmetic + XX X X X XXX + Opcode RD RS1 RS2 ddd + +### JR-Type, Compare and Jump + XX X X X XXX + Opcode Jump Condition RS1 RS2 ddd + +### JI-Type, Compare and Jump + XX X X XXXX + Opcode Jump Condition RS1 IMM + +## Registers + Maximum registers = 16 + Register width = 32 + All are R/W except 0X + + 0X Always Zero + AX GP-0 + BX GP-1 + CX GP-2 + DX GP-3 + EX GP-4 + FX GP-5 + GX GP-6 + HX GP-7 + HI Mult/Div Hi + LO Mult/Div Lo + FG Processor Flags + CR Control register (Writable only in supervisor mode) + IP Instruction Pointer + SP Stack Pointer + JA Jump Address + + ^ I have added this, it is part of my proposal for changing how jumps work + + +### FG Flag Register Bitfield + These registers are Read/Write + They are automaticaly writen two by the processor + + FG[0] Carry + FG[1] Overflow + FG[2] Zero + FG[3] Sign + FG[4-31] RESERVED + +### CR Control Register Bitfield + These register are Read/Write in System mode, Read Only in User Mode + + CR[0] Interupt Enable + CR[1] User Mode + CR[2] DMA + CR[2-31] RESERVED + + + +## Integer Instructions + +### R-Type + ADD RD, RS1, RS2 RD = RS1 + RS2 + SUB RD, RS1, RS2 RD = RS1 - RS2 + XOR RD, RS1, RS2 RD = RS1 ^ RS2 + OR RD, RS1, RS2 RD = RS1 | RS2 + AND RD, RS1, RS2 RD = RS1 & RS2 + LSL RD, RS1, RS2 RD = RS1 << RS2 (logical) + LSR RD, RS1, RS2 RD = RS1 >> RS2 (logical) + ASR RD, RS1, RS2 RD = RS1 >> RS2 + MUL RD, RS1, RS2 HI,LO = RS1 * RS2 + MULU RD, RS1, RS2 HI,LO = RS1 * RS2 + DIV RD, RS1, RS2 HI,LO = RS1 / RS2 + DIVU RD, RS1, RS2 HI,LO = RS1 / RS2 (unsigned) + + #LDB RD, RS1, RS2 RD = &(RS1 + RS2) Load Byte + #STB RD, RS1, RS2 &(RS1 + RS2) = (RD >> 24) Store Byte + LDW RD, RS1, RS2 RD = &(RS1 + RS2) Load Word (4 bytes) + STW RD, RS1, RS2 &(RS1 + RS2) = RD Store Word (4 bytes) + + # Depricated? + + +### I-Type + ADDI RD, RS, IMM RD = RS + IMM + SUBI RD, RS, IMM RD = RS - IMM + XORI RD, RS, IMM RD = RS ^ IMM + ORI RD, RS, IMM RD = RS | IMM + ANDI RD, RS, IMM RD = RS & IMM + LSLI RD, RS, IMM RD = RS << IMM (logical) + LSRI RD, RS, IMM RD = RS >> IMM (logical) + ASRI RD, RS, IMM RD = RS >> IMM + MULI dd, RS, IMM HI,LO = RS * IMM + MULIU dd, RS, IMM HI,LO = RS * IMM + DIVI dd, RS, IMM HI,LO = RS / IMM + DIVIU dd, RS, IMM HI,LO = RS / IMM (unsigned) + + #LDBI RD, RS, RS2 RD = &(RS + IMM) Load Byte + #STBI RD, RS, RS2 &(RS + IMM) = (RD >> 24) Store Byte + LDWI RD, RS, RS2 RD = &(RS + IMM) Load Word (4 bytes) + STWI RD, RS, RS2 &(RS + IMM) = RD Store Word (4 bytes) + + # Depricated? + + +### JR Instructions + Compare and then jump (IP = JMP) + + JMP 0 if (True) + JMP 1 if (RS1 != RS2) + JMP 2 if (RS1 == RS2) + JMP 3 if (RS1 > RS2) Unsigned + JMP 4 if (RS1 >= RS2) Unsigned + + JMP C if (RS1 > RS2) Signed + JMP D if (RS1 >= RS2) Signed + +### JI Instructions + Compare and then jump (IP = JMP) + + JMPI 0 if (True) + JMPI 1 if (RS1 != IMM) + JMPI 2 if (RS1 == IMM) + JMPI 3 if (RS1 > IMM) Unsigned + JMPI 4 if (RS1 >= IMM) Unsigned + + JMPI C if (RS1 > IMM) Signed + JMPI D if (RS1 >= IMM) Signed + +### Jump Aliases + + JEQ + JLT + JGT + JLE + JGE + JLTU + JGTU + JLEU + JGEU + + +### Control Instructions + NOP Do nothing -> opcode = ZERO + PUSHR RS SP+=1 ;*SP = RS + POPR RS RS = *SP ;SP-=1 + PUSHA PUSHR AX, BX, CX, DX, EX, FX, GX, FX, HI, LO, FG, CR, IP, SP, JA + POPA POP reverse PUSHR, SP not affected + PUSHI IMM SP+=1 ;*SP = IMM + INVP IMM Invalidate entry in TLB + RET POPR IP; + CALL PUSHR IP; IP = JMP; + INT PUSHA ;IP = IDT[IMM] + IRET POPR FLG; POPR SP; POPR IP + SIF Set interrupt flag + CIF Clear interrupt flag + +## Interrupt Descriptor Table +This will be in a fixed memory location, this will contain pointers to the interupt function. Once an interupt is entered, all interupts are turned off. + + IDT[0] Divide-by-zero exception + IDT[1] Hardware error (NMI) + IDT[2] Overflow + IDT[3] Invalid Opcode + IDT[4] General-protection fault + IDT[5] TLB miss + IDT[6] Software interrupt (reserved for OS) + IDT[7-31] Platform interrupts (PIC, hard drive, keyboard, etc.) + + IDTMSK[0-31] Interupt mask, when interupt is entered the mask bit for the coorisponding interupt will be disabled. + The software is responsible for renabling the mask bit + +You get 32 :) +Also, I was think of making the OS handle TLP misses + + + + + +## Page Directory + +The page directory contains 1024 page tables that have 1024 entries. + +^ Stupid question: Do we need a page directory? Also I have a very limited size for cache, idt, tlb, etc. Plan on having around 100 Kbits + +### Page table layout + + PT[0] Present + PT[1] R/W + PT[2] User-mode + PT[3-4] RESERVED + PT[5] Accessed + PT[6-7] RESERVED + PT[8-31] Physical address of page table (XX * 2^16 + XXXX) + + *This is still WIP but I wanted to get your input on the layout. I also have + the jank memory offset that will more than likely change.* -- cgit v1.2.3