Witch of Git - jade-rose/blob - isa.txt

   1 ROSE-8 v0.2.2
   2 ISA by Jordan Rose
   3 https://belkadan.com/source/ROSE-8/
   4
   5 * Eight completely symmetric general-purpose registers (r0-7) - initially 0
   6 * pc (16-bit address) - initially 0
   7 * it (accumulator) - initially 0
   8 * code (segment) - initially 1
   9 * data1 (segment) - initially 255
  10 * data2 (segment) - initially 254
  11
  12 7654_3210
  13
  14 0000_0000 STOP halts execution, like an invalid instruction
  15      0001 NOPE "no operation" (with a more fun mnemonic)
  16      0010 PRNT print it (for debugging or toy programs)
  17      0011 WAIT spin or sleep until data1[it] > 0, then decrement data1[it] (for MMIO)
  18      010x
  19      0110 CABA call absolute code[it], it <- return addr, code <- return segment
  20      0111 COFA call offset pc ± it, it <- return offset (-it + 1)
  21
  22 0000_1ooo ALU1 it <- {zero, lsl1, lsr1, asr1, incr, decr, comp, negt} it
  23
  24 0001_0000 GET1 it <- data1
  25      0001 GET2 it <- data2
  26      0010 GETC it <- code
  27      0011      (reserved for another special register)
  28      01xx
  29      1000 SET1 data1 <- it
  30      1001 SET2 data2 <- it
  31      1010 SETC code  <- it
  32      1011      (reserved for another special register)
  33      11xx
  34
  35 0010_0aaa GETR it <- it
  36    0_1aaa SETR ra <- it
  37    1_0aaa SWAP ra <- it, it <- ra
  38    1_1aaa ISLT "is less than", for testing overflow / carries: it <- (it < ra) ? 1 : 0
  39
  40 01oo_oaaa ALUR it <- it {addr, subr, andr, iorr, xorr, lslr, lsrr, asrr} ra
  41
  42 1000_0aaa LD1R it <- data1[ra]
  43   00_1aaa ST1R data1[ra] <- it
  44   01_0aaa LD1U it <- data1[ra], then ra += 1
  45   01_1aaa ST1U data1[ra] <- it, then ra += 1
  46   10_0aaa LD2R it <- data2[ra]
  47   10_1aaa ST2R data2[ra] <- it
  48   11_0aaa LD2U it <- data2[ra], then ra += 1
  49   11_1aaa ST2U data2[ra] <- it, then ra += 1
  50
  51 110x_xaaa               (reserved w/ register)
  52
  53 1110_0aaa LD2D ra -= 1, then it <- data2[ra]
  54 1110_1aaa ST2D ra -= 1, then data2[ra] <- it
  55
  56 1111_00oo iiiiiiii ALUI it <- it {andi, iori, xori, (see below)} i
  57      0011 0iiiiiii ADDI it <- it + i
  58      0011 10oooiii BITI it <- it {roli, lsli, lsri, asri, (clri), (insi), (togi), exti} i
  59      0011 11iiiiii ADDI it <- it + (whole field, thus allowing many negative numbers)
  60      0100 iiiiiiii BEZI branch pc ± i if it == 0
  61      0101 iiiiiiii JOFI jump offset to pc ± i
  62      0110 iiiiiiii CABI call absolute code[i], it <- return addr, code <- return segment
  63      0111 iiiiiiii COFI call offset pc ± i, it <- return offset (-i + 2)
  64      10xx iiiiiiii      (reserved w/ immediate)
  65      110x iiiiiiii      (reserved w/ immediate)
  66      1110 iiiiiiii GETI it <- i
  67      1111 xxxxxxxx EXT1 extended encoding for "future-proofing"