diff options
Diffstat (limited to 'triscv')
| -rw-r--r-- | triscv/README.md | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/triscv/README.md b/triscv/README.md index 62ad4b6..4adf17d 100644 --- a/triscv/README.md +++ b/triscv/README.md @@ -25,6 +25,7 @@ M-mode/S-mode/U-mode fits pretty nicely into trinary, heh. 27 trit ops, registers 3^4? +``` 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 |-----------------------------------------------------| @@ -38,6 +39,8 @@ M-mode/S-mode/U-mode fits pretty nicely into trinary, heh. |-----------------------------------------------------| | imm5 | rs2 | rs1 | immd | rd | opcode | D-type |-----------------------------------------------------| +``` + (D is a variant of R, where immd is actually fn0, but used as an immediate) Compressed instructions probably possible to implement in future but left alone @@ -65,6 +68,7 @@ like 32bit computers tend to use. Page table entries: +``` 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 |-----------------------------------------------------| @@ -74,6 +78,7 @@ Page table entries: |-----------------------------------------------------| | Reserved | |-----------------------------------------------------| +``` TAG is a tag that allows us to separate one address space into multiple regions, similar to CODOMS system but scaled down a lot. If left 0, code executing in the @@ -86,9 +91,11 @@ now. R/W and A/D work by the following table: +``` N => both (R and W, A and D) O => none P => top (R, A) +``` RSW is reserved for S-mode usage. @@ -129,80 +136,110 @@ TDB ## I addi, slti +``` |-----------------------------------------------------| | imm0 | rs1 | fn0 | rd | OP-IMM | I-type |-----------------------------------------------------| +``` unop (some macro instructions might be available in assembler) +``` |-----------------------------------------------------| | 0 |N|O|P| rs1 | fn0 | rd | OP-IMM | I-type |-----------------------------------------------------| +``` slli, srli (shifts work differently in balanced forms, have to be careful) (shmt is 'unsigned', i.e. the actual shift amount is shmt + 13) +``` |-----------------------------------------------------| | imm0 |shmt | rs1 | fn0 | rd | OP-IMM | I-type |-----------------------------------------------------| +``` lui +``` |-----------------------------------------------------| | imm18 | rd | LUI | U-type |-----------------------------------------------------| +``` auipc +``` |-----------------------------------------------------| | imm18 | rd | AUIPC | U-type |-----------------------------------------------------| +``` add, slt, sge, seq, sne, sll, srl, sub +``` |-----------------------------------------------------| | 0 | rs2 | rs1 | fn0 | rd | OP | R-type |-----------------------------------------------------| +``` diop +``` |-----------------------------------------------------| |N|O|P|N|O| rs2 | rs1 |P|N|O|P|0| rd | DIOP | D-type |-----------------------------------------------------| +``` nop +``` |-----------------------------------------------------| | 0 | x0 | 0 | x0 | OP-IMM | I-type |-----------------------------------------------------| +``` jal +``` |-----------------------------------------------------| | imm9 | rd | JAL | U-type |-----------------------------------------------------| +``` jalr +``` |-----------------------------------------------------| | imm0 | rs1 | 0 | rd | JALR | I-type |-----------------------------------------------------| +``` beq, bne, blt, bge +``` |-----------------------------------------------------| | imm0 | rs2 | rs1 | fn0 | imm4 | BRANCH | S-type |-----------------------------------------------------| +``` load (w = width, i = 1 tryte, 0 = 3 trytes, 1 = 9 trytes) +``` |-----------------------------------------------------| | imm0 | rs1 |w| 0 | rd | LOAD | I-type |-----------------------------------------------------| +``` store +``` |-----------------------------------------------------| | imm5 | rs2 | rs1 |w| 0 | imm4 | STORE | S-type |-----------------------------------------------------| +``` fence (todo) +``` |-----------------------------------------------------| | imm0 | rs1 | fn0 | rd | MEM | I-type |-----------------------------------------------------| +``` ecall, ebreak, pcall +``` |-----------------------------------------------------| | imm0 | x0 | fn0 | x0 | SYSTEM | I-type |-----------------------------------------------------| +``` hints, any OP-IMM or OP with rd = x0. Additionally, a number of maybe-instructions in SYSTEM for future use, if unimplemented @@ -211,19 +248,25 @@ just write 0 to rd. ## M mul +``` |-----------------------------------------------------| | fn5 | rs2 | rs1 | fn0 | rd | OP | R-type |-----------------------------------------------------| +``` div +``` |-----------------------------------------------------| | fn5 | rs2 | rs1 | fn0 | rd | OP | R-type |-----------------------------------------------------| +``` rem +``` |-----------------------------------------------------| | fn5 | rs2 | rs1 | fn0 | rd | OP | R-type |-----------------------------------------------------| +``` ## A @@ -241,6 +284,7 @@ somewhere. Platforms may require at least n slots. Maybe? Reads inside transaction read from memory. Slow commits, at least somewhat, but probably somewhat simpler. Spinlock (and by extension, mutex) would then be +``` spinlock: // spin until a zero appears lw x1, (x2) @@ -256,15 +300,18 @@ spinlock: // avoid livelock, or rely on whatever system we're dealing with to // provide it for us beqz x1, spinlock +``` could probably also provide simple atomics, like add or something, but eh ## Zicsr csrrw, csrrs, csrrc +``` |-----------------------------------------------------| | imm0 | rs | fn0 | rd | SYSTEM | I-type |-----------------------------------------------------| +`` The CSR numbers are specified in the future. |