# primitives for emitting traces to a 'trace' stream, and for tests to make assertions on its contents # # A trace stream looks like a regular stream: # write: int # index at which writes go # read: int # index that we've read until # data: (array byte) # prefixed by size as usual # Usually the trace stream will be in a separate segment set aside for the purpose. # # primitives for operating on traces (arguments in quotes): # - initialize-trace-stream: populates Trace-stream with a new segment of the given 'size' # - trace: adds a 'line' to Trace-stream # - check-trace-contains: scans from Trace-stream's start for a matching 'line', prints a 'message' to stderr on failure # - check-trace-scans-to: scans from Trace-stream's read pointer for a matching 'line', prints a 'message' to stderr on failure == data Trace-stream: # (addr stream byte) # TODO: make this a handle 0/imm32 Trace-segment: 0/imm32/curr 0/imm32/limit # Fake trace-stream for tests. # Also illustrates the layout of the real trace-stream (segment). _test-trace-stream: # (stream byte) # current write index 0/imm32 # current read index 0/imm32 # size 8/imm32 # data 00 00 00 00 00 00 00 00 # 8 bytes == code # instruction effective address register displacement immediate # . op subop mod rm32 base index scale r32 # . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes # Allocate a new segment for the trace stream, initialize its size, and save its address to Trace-stream. # The Trace-stream segment will consist of variable-length lines separated by newlines (0x0a) initialize-trace-stream: # n: int # . prologue 55/push-ebp 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp # . save registers 50/push-eax 51/push-ecx # ecx = n 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx # Trace-segment = new-segment(n) # . . push args 68/push Trace-segment/imm32 51/push-ecx # . . call e8/call new-segment/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp # copy Trace-segment->curr to *Trace-stream 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/eax Trace-segment/disp32 # copy *Trace-segment to eax #? # watch point to catch Trace-stream leaks #? $watch-1: 89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/eax Trace-stream/disp32 # copy eax to *Trace-stream # Trace-stream->size = n - 12 # . ecx -= 12 81 5/subop/subtract 3/mod/direct 1/rm32/ecx . . . . . 0xc/imm32 # subtract from ecx # . Trace-stream->size = ecx 89/copy 1/mod/*+disp8 0/rm32/eax . . . 1/r32/ecx 8/disp8 . # copy ecx to *(eax+8) $initialize-trace-stream:end: # . restore registers 59/pop-to-ecx 58/pop-to-eax # . epilogue 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 5d/pop-to-ebp c3/return # Append a string to the given trace stream. # Silently give up if it's already full. Or truncate the string if there isn't enough room. trace: # line: (addr array byte) # . prologue 55/push-ebp 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp # . save registers 50/push-eax 51/push-ecx 52/push-edx 53/push-ebx 56/push-esi 57/push-edi # var edi: (addr stream byte) = *Trace-stream 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 7/r32/edi Trace-stream/disp32 # copy *Trace-stream to edi # esi = line 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 6/r32/esi 8/disp8 . # copy *(ebp+8) to esi # var ecx: int = t->write 8b/copy 0/mod/indirect 7/rm32/edi . . . 1/r32/ecx . . # copy *edi to ecx # var edx: int = t->size 8b/copy 1/mod/*+disp8 7/rm32/edi . . . 2/r32/edx 8/disp8 . # copy *(edi+8) to edx # eax = _append-3(&t->data[t->write], &t->data[t->size], line) # . . push line 56/push-esi # . . push &t->data[t->size] 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 2/index/edx . 3/r32/ebx 0xc/disp8 . # copy edi+edx+12 to ebx 53/push-ebx # . . push &t->data[t->write] 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 1/index/ecx . 3/r32/ebx 0xc/disp8 . # copy edi+ecx+12 to ebx 53/push-ebx # . . call e8/call _append-3/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp # if (eax == 0) return 3d/compare-eax-and 0/imm32 74/jump-if-= $trace:end/disp8 # t->write += eax 01/add 0/mod/indirect 7/rm32/edi . . . 0/r32/eax . . # add eax to *edi # refresh ecx = t->write 8b/copy 0/mod/indirect 7/rm32/edi . . . 1/r32/ecx . . # copy *edi to ecx # eax = _append-3(&t->data[t->write], &t->data[t->size], line) # . . push line 68/push Newline/imm32 # . . push &t->data[t->size] 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 2/index/edx . 3/r32/ebx 0xc/disp8 . # copy edi+edx+12 to ebx 53/push-ebx # . . push &t->data[t->write] 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 1/index/ecx . 3/r32/ebx 0xc/disp8 . # copy edi+ecx+12 to ebx 53/push-ebx # . . call e8/call _append-3/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp # t->write += eax 01/add 0/mod/indirect 7/rm32/edi . . . 0/r32/eax . . # add eax to *edi $trace:end: # . restore registers 5f/pop-to-edi 5e/pop-to-esi 5b/pop-to-ebx 5a/pop-to-edx 59/pop-to-ecx 58/pop-to-eax # . epilogue 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 5d/pop-to-ebp c3/return test-trace-single: # push *Trace-stream ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Trace-stream/disp32 # push *Trace-stream # *Trace-stream = _test-trace-stream b8/copy-to-eax _test-trace-stream/imm32 89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/eax Trace-stream/disp32 # copy eax to *Trace-stream # clear-trace-stream() e8/call clear-trace-stream/disp32 # trace("Ab") # . . push args 68/push "Ab"/imm32 # . . call e8/call trace/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp # check-ints-equal(*_test-trace-stream->data, 41/A 62/b 0a/newline 00, msg) # . . push args 68/push "F - test-trace-single"/imm32 68/push 0x0a6241/imm32/Ab-newline # . . push *_test-trace-stream->data b8/copy-to-eax _test-trace-stream/imm32 ff 6/subop/push 1/mod/*+disp8 0/rm32/eax . . . . 0xc/disp8 . # push *(eax+12) # . . call e8/call check-ints-equal/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/esp . . .
# 32-bit fixed-point number, with 6 bits of precision.
type LayoutUnit* = distinct int32
func `==`*(a, b: LayoutUnit): bool {.borrow.}
func `<`*(a, b: LayoutUnit): bool {.borrow.}
func `<=`*(a, b: LayoutUnit): bool {.borrow.}
func `+`*(a, b: LayoutUnit): LayoutUnit {.borrow.}
func `+=`*(a: var LayoutUnit, b: LayoutUnit) {.borrow.}
func `-`*(a, b: LayoutUnit): LayoutUnit {.borrow.}
func `-`*(a: LayoutUnit): LayoutUnit {.borrow.}
func `-=`*(a: var LayoutUnit, b: LayoutUnit) {.borrow.}
func `*`*(a, b: LayoutUnit): LayoutUnit {.inline.} =
LayoutUnit((int32(a) * int32(b)) shr 6)
func `*=`*(a: var LayoutUnit, b: LayoutUnit) {.inline.} =
a = a * b
func `/`*(a, b: LayoutUnit): LayoutUnit {.inline.} =
let a64 = int64(a)
let b64 = int64(b)
LayoutUnit(cast[int32](((a64 shl 12) div b64) shr 6))
func `/=`*(a: var LayoutUnit, b: LayoutUnit) {.inline.} =
a = a / b
func `div`*(a, b: LayoutUnit): LayoutUnit {.inline.} =
a / b
func toInt*(a: LayoutUnit): int =
return int32(a) shr 6
converter toLayoutUnit*(a: int32): LayoutUnit =
return LayoutUnit(a shl 6)
converter toLayoutUnit*(a: int64): LayoutUnit =
return toLayoutUnit(cast[int32](a))
converter toLayoutUnit*(a: int): LayoutUnit =
return toLayoutUnit(cast[int32](a))
converter toLayoutUnit*(a: float64): LayoutUnit =
if unlikely(a == Inf):
return LayoutUnit(high(int32))
elif unlikely(a == -Inf):
return LayoutUnit(low(int32))
return LayoutUnit(int32(a * 64))
func toFloat64*(a: LayoutUnit): float64 =
return float64(int32(a)) / 64
func `$`*(a: LayoutUnit): string =
$toFloat64(a)
func min*(a, b: LayoutUnit): LayoutUnit {.borrow.}
func max*(a, b: LayoutUnit): LayoutUnit {.borrow.}
func clamp*(x, a, b: LayoutUnit): LayoutUnit {.borrow.}
func round*(a: LayoutUnit; prec: int): LayoutUnit =
return (a div prec).toInt * prec