start distinguishing table lookups from inserts

1 files changed, 370 insertions, 0 deletions

diff --git a/subx/apps/subx-common.subx b/subx/apps/subx-common.subx
index 129c9821..083e6cc2 100644
--- a/subx/apps/subx-common.subx
+++ b/subx/apps/subx-common.subx
@@ -5,6 +5,376 @@
 # . 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
 
+# - managing tables
+# SubX has rudimentary support for tables.
+#
+# Each table is a stream of rows.
+#
+# Each row consists of a 4-byte row (address to a string) and a variable-size
+# value.
+#
+# Accessing the table performs a linear scan for a key string, and always
+# requires passing in the row size.
+#
+# Table primitives:
+#   get(stream, string, row-size)
+#     aborts if not found
+#   get-or-insert(stream, string, row-size)
+#     inserts if not found
+#   get-slice(stream, slice, row-size)
+#     aborts if not found
+#   get-or-insert-slice(stream, slice, row-size)
+#     inserts if not found
+
+# 'table' is a stream of (key, value) rows
+# keys are always strings (addresses; size 4 bytes)
+# values may be any type, but rows (key+value) always occupy 'row-size' bytes
+# scan 'table' for a row with a key 'key' and return the address of the corresponding value
+# if no row is found, abort
+get:  # table : (address stream {string, _}), key : (address string), row-size : int -> EAX : (address _)
+    # pseudocode:
+    #   curr = table->data
+    #   max = &table->data[table->write]
+    #   while curr < max
+    #     if string-equal?(key, *curr)
+    #       return curr+4
+    #     curr += row-size
+    #   abort
+    #
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # . save registers
+    51/push-ECX
+    52/push-EDX
+    56/push-ESI
+    # ESI = table
+    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
+    # curr/ECX = table->data
+    8d/copy-address                 1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   0xc/disp8       .                 # copy ESI+12 to ECX
+    # max/EDX = table->data + table->write
+    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           2/r32/EDX   .               .                 # copy *ESI to EDX
+    8d/copy-address                 0/mod/indirect  4/rm32/sib    1/base/ECX  2/index/EDX   .           2/r32/EDX   .               .                 # copy ECX+EDX to EDX
+$get:search-loop:
+    # if (curr >= max) abort
+    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
+    73/jump-if-greater-or-equal-unsigned  $get:abort/disp8
+    # if (string-equal?(key, *curr)) return curr+4
+    # . EAX = string-equal?(key, *curr)
+    # . . push args
+    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
+    # . . call
+    e8/call  string-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . if (EAX != 0) return EAX = curr+4
+    3d/compare-EAX-and  0/imm32
+    74/jump-if-equal  $get:mismatch/disp8
+    8d/copy-address                 1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy ECX+4 to EAX
+    eb/jump  $get:end/disp8
+$get:mismatch:
+    # curr += row-size
+    03/add                          1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   0x10/disp8      .                 # add *(EBP+16) to ECX
+    # loop
+    eb/jump  $get:search-loop/disp8
+$get:end:
+    # . restore registers
+    5e/pop-to-ESI
+    5a/pop-to-EDX
+    59/pop-to-ECX
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+$get:abort:
+    # . _write(2/stderr, error)
+    # . . push args
+    68/push  "get: key not found: "/imm32
+    68/push  2/imm32/stderr
+    # . . call
+    e8/call  _write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . _write(2/stderr, key)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
+    68/push  2/imm32/stderr
+    # . . call
+    e8/call  _write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . syscall(exit, 1)
+    bb/copy-to-EBX  1/imm32
+    b8/copy-to-EAX  1/imm32/exit
+    cd/syscall  0x80/imm8
+    # never gets here
+
+test-get:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # - setup: create a table with a couple of keys
+    # var table/ECX : (address stream {string, number}) = stream(2 rows * 8 bytes)
+    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # subtract from ESP
+    68/push  0x10/imm32/length
+    68/push  0/imm32/read
+    68/push  0/imm32/write
+    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
+    # insert(table, "code", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    68/push  "code"/imm32
+    51/push-ECX
+    # . . call
+    e8/call  get-or-insert/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # insert(table, "data", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    68/push  "data"/imm32
+    51/push-ECX
+    # . . call
+    e8/call  get-or-insert/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+$test-get:check1:
+    # EAX = get(table, "code", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    68/push  "code"/imm32
+    51/push-ECX
+    # . . call
+    e8/call  get/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # check-ints-equal(EAX - table->data, 4, msg)
+    # . check-ints-equal(EAX - table, 16, msg)
+    # . . push args
+    68/push  "F - test-get/0"/imm32
+    68/push  0x10/imm32
+    29/subtract                     3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # subtract ECX from EAX
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+$test-get:check2:
+    # EAX = get(table, "data", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    68/push  "data"/imm32
+    51/push-ECX
+    # . . call
+    e8/call  get/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # check-ints-equal(EAX - table->data, 12, msg)
+    # . check-ints-equal(EAX - table, 24, msg)
+    # . . push args
+    68/push  "F - test-get/1"/imm32
+    68/push  0x18/imm32
+    29/subtract                     3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # subtract ECX from EAX
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+$test-get:end:
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+# 'table' is a stream of (key, value) rows
+# keys are always strings (addresses; size 4 bytes)
+# values may be any type, but rows (key+value) always occupy 'row-size' bytes
+# scan 'table' for a row with a key 'key' and return the address of the corresponding value
+# if no row is found, abort
+get-slice:  # table : (address stream {string, _}), key : (address slice), row-size : int -> EAX : (address _)
+    # pseudocode:
+    #   curr = table->data
+    #   max = &table->data[table->write]
+    #   while curr < max
+    #     if slice-equal?(key, *curr)
+    #       return curr+4
+    #     curr += row-size
+    #   abort
+    #
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # . save registers
+    51/push-ECX
+    52/push-EDX
+    56/push-ESI
+    # ESI = table
+    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
+    # curr/ECX = table->data
+    8d/copy-address                 1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   0xc/disp8       .                 # copy ESI+12 to ECX
+    # max/EDX = table->data + table->write
+    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           2/r32/EDX   .               .                 # copy *ESI to EDX
+    8d/copy-address                 0/mod/indirect  4/rm32/sib    1/base/ECX  2/index/EDX   .           2/r32/EDX   .               .                 # copy ECX+EDX to EDX
+$get-slice:search-loop:
+    # if (curr >= max) abort
+    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
+    73/jump-if-greater-or-equal-unsigned  $get-slice:abort/disp8
+    # if (slice-equal?(key, *curr)) return curr+4
+    # . EAX = slice-equal?(key, *curr)
+    # . . push args
+    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
+    # . . call
+    e8/call  slice-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . if (EAX != 0) return EAX = curr+4
+    3d/compare-EAX-and  0/imm32
+    74/jump-if-equal  $get-slice:mismatch/disp8
+    8d/copy-address                 1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy ECX+4 to EAX
+    eb/jump  $get-slice:end/disp8
+$get-slice:mismatch:
+    # curr += row-size
+    03/add                          1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   0x10/disp8      .                 # add *(EBP+16) to ECX
+    # loop
+    eb/jump  $get-slice:search-loop/disp8
+$get-slice:end:
+    # . restore registers
+    5e/pop-to-ESI
+    5a/pop-to-EDX
+    59/pop-to-ECX
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+$get-slice:abort:
+    # . _write(2/stderr, error)
+    # . . push args
+    68/push  "get-slice: key not found: "/imm32
+    68/push  2/imm32/stderr
+    # . . call
+    e8/call  _write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write-slice-buffered(Stderr, key)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  write-slice-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . flush(Stderr)
+    # . . push args
+    68/push  Stderr/imm32
+    # . . call
+    e8/call  flush/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # . syscall(exit, 1)
+    bb/copy-to-EBX  1/imm32
+    b8/copy-to-EAX  1/imm32/exit
+    cd/syscall  0x80/imm8
+    # never gets here
+
+test-get-slice:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # - setup: create a table with a couple of keys
+    # var table/ECX : (address stream {string, number}) = stream(2 rows * 8 bytes)
+    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # subtract from ESP
+    68/push  0x10/imm32/length
+    68/push  0/imm32/read
+    68/push  0/imm32/write
+    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
+    # insert(table, "code", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    68/push  "code"/imm32
+    51/push-ECX
+    # . . call
+    e8/call  get-or-insert/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # insert(table, "data", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    68/push  "data"/imm32
+    51/push-ECX
+    # . . call
+    e8/call  get-or-insert/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+$test-get-slice:check1:
+    # (EAX..EDX) = "code"
+    b8/copy-to-EAX  "code"/imm32
+    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # copy *EAX to EDX
+    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  2/index/EDX   .           2/r32/EDX   4/disp8         .                 # copy EAX+EDX+4 to EDX
+    05/add-to-EAX  4/imm32
+    # var slice/EDX = {EAX, EDX}
+    52/push-EDX
+    50/push-EAX
+    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
+    # EAX = get-slice(table, "code", 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    52/push-EDX
+    51/push-ECX
+    # . . call
+    e8/call  get-slice/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # check-ints-equal(EAX - table->data, 4, msg)  # first row's value slot returned
+    # . check-ints-equal(EAX - table, 16, msg)
+    # . . push args
+    68/push  "F - test-get-slice/0"/imm32
+    68/push  0x10/imm32
+    29/subtract                     3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # subtract ECX from EAX
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+$test-get-slice:check2:
+    # (EAX..EDX) = "data"
+    b8/copy-to-EAX  "data"/imm32
+    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # copy *EAX to EDX
+    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  2/index/EDX   .           2/r32/EDX   4/disp8         .                 # copy EAX+EDX+4 to EDX
+    05/add-to-EAX  4/imm32
+    # var slice/EDX = {EAX, EDX}
+    52/push-EDX
+    50/push-EAX
+    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
+    # EAX = get-slice(table, "data" slice, 8 bytes per row)
+    # . . push args
+    68/push  8/imm32/row-size
+    52/push-EDX
+    51/push-ECX
+    # . . call
+    e8/call  get-slice/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # check-ints-equal(EAX - table->data, 12, msg)
+    # . check-ints-equal(EAX - table, 24, msg)
+    # . . push args
+    68/push  "F - test-get-slice/1"/imm32
+    68/push  0x18/imm32
+    29/subtract                     3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # subtract ECX from EAX
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+$test-get-slice:end:
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
 # 'table' is a stream of (key, value) rows
 # keys are always strings (addresses; size 4 bytes)
 # values may be any type, but rows (key+value) always occupy 'row-size' bytes