diff options
Diffstat (limited to 'linux/mu-init.subx')
| -rw-r--r-- | linux/mu-init.subx | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/linux/mu-init.subx b/linux/mu-init.subx new file mode 100644 index 00000000..feab920f --- /dev/null +++ b/linux/mu-init.subx @@ -0,0 +1,62 @@ +# Initialize the minimal runtime for Mu programs. +# +# See translate_mu for how this file is used. +# +# Mu programs start at a function called 'main' with this signature: +# fn main args: (addr array addr array byte) -> _/ebx: int +# If your program doesn't need commandline arguments you can drop it: +# fn main -> _/ebx: int +# +# Notice that the output must be in ebx, so that the exit() syscall can pick +# it up. + +== code + +Entry: + # we don't use ebp in Entry; just initialize it + bd/copy-to-ebp 0/imm32 + # - save argc and argv + # var argc-and-argv/esi + 89/<- %esi 4/r32/esp +$Entry:initialize-heap: + # - initialize the heap + (new-segment *Heap-size Heap) +$Entry:initialize-args: + # - convert argv from null-terminated 'kernel' strings to length-prefixed Mu strings + # var argc/edx: int + 8b/-> *esi 2/r32/edx + # argc is in words; convert it to bytes + c1/shift 4/subop/left %edx 2/imm8 + # var tmp/ebx: handle + 68/push 0/imm32 + 68/push 0/imm32 + 89/<- %ebx 4/r32/esp + # var args/edi: (addr array (addr array byte)) + (allocate-array Heap %edx %ebx) + (lookup *ebx *(ebx+4)) # => eax + 89/<- %edi 0/r32/eax + # var curr/ecx: (addr kernel-string) = argv + 8d/copy-address *(esi+4) 1/r32/ecx + # var max/edx: (addr kernel-string) = argv+4+argc + 8d/copy-address *(ecx+edx) 2/r32/edx + # var dest/esi: (addr (addr array byte)) = args+4 + 8d/copy-address *(edi+4) 6/r32/esi + { + # if (curr >= max) break + 39/compare %ecx 2/r32/edx + 73/jump-if-addr>= break/disp8 + # *dest = kernel-string-to-string(*curr) + (kernel-string-to-string Heap *ecx %ebx) + (lookup *ebx *(ebx+4)) # => eax + 89/<- *esi 0/r32/eax + # curr += 4 + 81 0/subop/add %ecx 4/imm32 + # dest += 4 + 81 0/subop/add %esi 4/imm32 + # + eb/jump loop/disp8 + } + # - run Mu program + (main %edi) # => ebx + # - exit + (syscall_exit) |