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perfaware/part1: Support listing 0047

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This commit is contained in:
doyle 2023-04-16 18:13:13 +10:00
parent 9c9a505464
commit 2a5b3461e3
7 changed files with 197 additions and 37 deletions
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7
part1/build.bat
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@ -85,3 +85,10 @@ copy /Y %script_dir%\%listing_0046%.txt %build_dir% 1>NUL
set build_dir_listing_0046=%build_dir%\%listing_0046%
%build_dir%\sim8086.exe --exec %build_dir_listing_0046% > %build_dir_listing_0046%_disassembled.txt
fc /N %build_dir_listing_0046%.txt %build_dir_listing_0046%_disassembled.txt || exit /b 1
set listing_0047=listing_0047_challenge_flags
copy /Y %script_dir%\%listing_0047% %build_dir% 1>NUL
copy /Y %script_dir%\%listing_0047%.txt %build_dir% 1>NUL
set build_dir_listing_0047=%build_dir%\%listing_0047%
%build_dir%\sim8086.exe --exec %build_dir_listing_0047% > %build_dir_listing_0047%_disassembled.txt
fc /N %build_dir_listing_0047%.txt %build_dir_listing_0047%_disassembled.txt || exit /b 1

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part1/listing_0047_challenge_flags Normal file
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36
part1/listing_0047_challenge_flags.asm Normal file
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@ -0,0 +1,36 @@
; ========================================================================
;
; (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
; arising from the use of this software.
;
; Please see https://computerenhance.com for further information
;
; ========================================================================
; ========================================================================
; LISTING 47
; ========================================================================
bits 16
add bx, 30000
add bx, 10000
sub bx, 5000
sub bx, 5000
mov bx, 1
mov cx, 100
add bx, cx
mov dx, 10
sub cx, dx
add bx, 40000
add cx, -90
mov sp, 99
mov bp, 98
cmp bp, sp

23
part1/listing_0047_challenge_flags.txt Normal file
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@ -0,0 +1,23 @@
--- test\listing_0047_challenge_flags execution ---
add bx, 30000 ; bx:0x0->0x7530 flags:->P
add bx, 10000 ; bx:0x7530->0x9c40 flags:P->SO
sub bx, 5000 ; bx:0x9c40->0x88b8 flags:SO->PAS
sub bx, 5000 ; bx:0x88b8->0x7530 flags:PAS->PO
mov bx, 1 ; bx:0x7530->0x1
mov cx, 100 ; cx:0x0->0x64
add bx, cx ; bx:0x1->0x65 flags:PO->P
mov dx, 10 ; dx:0x0->0xa
sub cx, dx ; cx:0x64->0x5a flags:P->PA
add bx, 40000 ; bx:0x65->0x9ca5 flags:PA->PS
add cx, -90 ; cx:0x5a->0x0 flags:PS->CPAZ
mov sp, 99 ; sp:0x0->0x63
mov bp, 98 ; bp:0x0->0x62
cmp bp, sp ; flags:CPAZ->CPAS
Final registers:
bx: 0x9ca5 (40101)
dx: 0x000a (10)
sp: 0x0063 (99)
bp: 0x0062 (98)
flags: CPAS

167
part1/sim8086.c
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@ -22,15 +22,16 @@ typedef enum S86_RegisterByte {
typedef union S86_Register16 {
uint16_t word;
struct { uint8_t lo; uint8_t hi; } byte;
uint8_t bytes[S86_RegisterByte_Count];
} S86_Register16;
typedef struct S86_RegisterFileFlags {
bool carry;
bool zero;
bool sign;
bool parity;
bool overflow;
bool parity;
bool auxiliary_carry;
} S86_RegisterFileFlags;
typedef struct S86_RegisterFile {
@ -54,10 +55,12 @@ typedef struct S86_RegisterFile {
bool S86_RegisterFileFlagsEq(S86_RegisterFileFlags lhs, S86_RegisterFileFlags rhs)
{
bool result = lhs.sign == rhs.sign &&
lhs.zero == rhs.zero &&
lhs.parity == rhs.parity &&
lhs.overflow == rhs.overflow;
bool result = lhs.carry == rhs.carry &&
lhs.zero == rhs.zero &&
lhs.sign == rhs.sign &&
lhs.overflow == rhs.overflow &&
lhs.parity == rhs.parity &&
lhs.auxiliary_carry == rhs.auxiliary_carry;
return result;
}
@ -278,7 +281,11 @@ void S86_PrintOpcodeMnemonicOp(S86_Opcode opcode, bool src)
opcode.displacement > 0 ? '+' : '-',
opcode.displacement > 0 ? opcode.displacement : -opcode.displacement);
} else if (mnemonic_op == S86_MnemonicOp_Immediate) {
S86_PrintFmt("%u", opcode.immediate);
if (opcode.immediate_is_8bit) {
S86_PrintFmt("%d", (int8_t)opcode.immediate);
} else {
S86_PrintFmt("%u", (uint16_t)opcode.immediate);
}
} else if (mnemonic_op == S86_MnemonicOp_DirectInterSegment) {
uint16_t left = (uint32_t)opcode.displacement >> 16;
uint16_t right = (uint32_t)opcode.displacement & 0xFFFF;
@ -623,8 +630,14 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
op_decode_type == S86_OpDecodeType_TESTImmediateAndRegOrMem ||
op_decode_type == S86_OpDecodeType_ORImmediateToRegOrMem ||
op_decode_type == S86_OpDecodeType_XORImmediateToRegOrMem) && s) {
// NOTE: Sign extend 8 bit, since we store into a
// int32_t in opcode this is done for free for us.
// NOTE: Sign extend 8 bit to 16 bit
uint16_t sign_mask = 0b1000'0000;
uint8_t data_u8 = S86_CAST(uint8_t)data;
if (sign_mask & data_u8) {
data = (uint16_t)((uint8_t)~data_u8 + 1); // Convert back to 8 bit unsigned
data = ~data + 1; // Convert to 16bit signed
result.immediate_is_8bit = true;
}
} else {
uint8_t data_hi = S86_BufferIteratorNextByte(buffer_it);
data |= (uint16_t)(data_hi) << 8;
@ -635,8 +648,16 @@ S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
S86_ASSERT(mod != 0b11); // NOTE: Op is IMM->Reg, register-to-register not permitted
}
result.immediate = data;
result.src = S86_MnemonicOp_Immediate;
// NOTE: Sign extend 16bit to 32bit
uint16_t sign_mask16 = 0b1000'0000'0000'0000;
if (data & sign_mask16) {
uint32_t data_no_sign_bit = (uint32_t)((uint16_t)~data + 1); // Convert back to 16 bit unsigned
result.immediate = ~data_no_sign_bit + 1; // Convert to signed 32bit
} else {
result.immediate = data;
}
result.src = S86_MnemonicOp_Immediate;
if (op_decode_type == S86_OpDecodeType_MOVImmediateToRegOrMem)
result.wide_prefix = S86_WidePrefix_Src;
else if (result.effective_addr_loads_mem)
@ -1362,17 +1383,19 @@ int main(int argc, char **argv)
}
S86_ASSERT(dest_map);
uint16_t sign = opcode.mnemonic == S86_Mnemonic_ADD ? 1 : -1;
S86_Register16 dest = *dest_map->reg;
uint16_t prev_dest16 = dest.word;
bool byte_op = opcode.dest >= S86_MnemonicOp_AL && opcode.dest <= S86_MnemonicOp_BH;
bool subtract = opcode.mnemonic != S86_Mnemonic_ADD;
S86_Register16 dest = *dest_map->reg;
S86_Register16 prev_dest = dest;
bool byte_op = opcode.dest >= S86_MnemonicOp_AL && opcode.dest <= S86_MnemonicOp_BH;
uint16_t src = 0;
if (opcode.src == S86_MnemonicOp_Immediate) {
if (byte_op) {
S86_ASSERT(opcode.immediate < S86_CAST(uint8_t)-1);
dest.bytes[dest_map->byte] += S86_CAST(uint8_t)(opcode.immediate * sign);
src = S86_CAST(uint8_t)opcode.immediate;
} else {
S86_ASSERT(opcode.immediate < S86_CAST(uint16_t)-1);
dest.word += S86_CAST(uint16_t)(opcode.immediate * sign);
src = S86_CAST(uint16_t)opcode.immediate;
}
} else {
S86_MnemonicOpToRegisterFileMap const *src_map = NULL;
@ -1381,25 +1404,83 @@ int main(int argc, char **argv)
if (item->mnemonic_op == opcode.src)
src_map = item;
}
if (byte_op)
dest.bytes[dest_map->byte] += S86_CAST(uint8_t)(src_map->reg->bytes[src_map->byte] * sign);
else
dest.word += S86_CAST(uint16_t)(src_map->reg->word * sign);
src = byte_op ? src_map->reg->bytes[src_map->byte] : src_map->reg->word;
}
int bit_count = _mm_popcnt_u32(S86_CAST(uint32_t)dest.bytes[S86_RegisterByte_Lo]);
register_file.flags.parity = (bit_count % 2 == 0);
// NOTE: Overflow if the sign masks were initially the same,
// but, after the operation the sign masked changed.
uint8_t const sign_mask8 = 0b1000'0000;
uint16_t const sign_mask16 = 0b1000'0000'0000'0000;
if (byte_op) {
uint8_t src_u8 = S86_CAST(uint8_t)src;
if (subtract)
src_u8 = ~src_u8 + 1;
S86_Str8 dest_reg16 = S86_MnemonicOpStr8(dest_map->mnemonic_op_reg16);
register_file.flags.sign = dest_map->reg->word & (byte_op ? 0b0000'0000'1000'0000 : 0b1000'0000'0000'0000);
uint8_t dest_u8 = dest.bytes[dest_map->byte];
uint8_t new_dest_u8 = dest_u8 + src_u8;
// NOTE: Overflow check
bool initially_matching_sign_masks = (dest_u8 & sign_mask8) == (src_u8 & sign_mask8);
bool sign_masks_changed = (dest_u8 & sign_mask8) != (new_dest_u8 & sign_mask8);
register_file.flags.overflow = initially_matching_sign_masks && sign_masks_changed;
// NOTE: Carry check
register_file.flags.carry = subtract ? new_dest_u8 > dest_u8 : new_dest_u8 < dest_u8;
// NOTE: Auxiliary carry check
uint8_t dest_u8_nibble_lo = dest_u8 & 0b0000'1111 >> 0;
uint8_t dest_u8_nibble_hi = dest_u8 & 0b1111'0000 >> 4;
uint8_t new_dest_u8_nibble_lo = new_dest_u8 & 0b0000'1111 >> 0;
uint8_t new_dest_u8_nibble_hi = new_dest_u8 & 0b1111'0000 >> 4;
register_file.flags.auxiliary_carry = subtract ? new_dest_u8_nibble_hi > dest_u8_nibble_hi
: new_dest_u8_nibble_lo < dest_u8_nibble_lo;
// NOTE: Sign check
register_file.flags.sign = new_dest_u8 & 0b1000'0000;
// NOTE: Update the register
dest.bytes[dest_map->byte] = new_dest_u8;
} else {
if (subtract)
src = ~src + 1;
S86_Register16 new_dest = {0};
new_dest.word = dest.word + src;
// NOTE: Overflow check
bool initially_matching_sign_masks = (dest.word & sign_mask16) == (src & sign_mask16);
bool sign_masks_changed = (dest.word & sign_mask16) != (new_dest.word & sign_mask16);
register_file.flags.overflow = initially_matching_sign_masks && sign_masks_changed;
// NOTE: Auxiliary carry check
uint8_t dest_lo_nibble_lo = dest.bytes[S86_RegisterByte_Lo] & 0b0000'1111 >> 0;
uint8_t dest_lo_nibble_hi = dest.bytes[S86_RegisterByte_Lo] & 0b1111'0000 >> 4;
uint8_t new_dest_lo_nibble_lo = new_dest.bytes[S86_RegisterByte_Lo] & 0b0000'1111 >> 0;
uint8_t new_dest_lo_nibble_hi = new_dest.bytes[S86_RegisterByte_Lo] & 0b1111'0000 >> 4;
register_file.flags.auxiliary_carry = subtract ? new_dest_lo_nibble_hi > dest_lo_nibble_hi
: new_dest_lo_nibble_lo < dest_lo_nibble_lo;
// NOTE: Carry check
register_file.flags.carry = subtract ? new_dest.word > dest.word : new_dest.word < dest.word;
// NOTE: Sign check
register_file.flags.sign = new_dest.word & 0b1000'0000'0000'0000;
// NOTE: Update the register
dest.word = new_dest.word;
}
int lo_bit_count = _mm_popcnt_u32(S86_CAST(uint32_t)dest.bytes[S86_RegisterByte_Lo]);
register_file.flags.parity = lo_bit_count % 2 == 0;
register_file.flags.zero = false;
if (opcode.mnemonic == S86_Mnemonic_ADD || opcode.mnemonic == S86_Mnemonic_SUB)
register_file.flags.zero = byte_op ? dest.bytes[dest_map->byte] == 0 : dest.word == 0;
if (opcode.mnemonic == S86_Mnemonic_CMP) {
S86_PrintFmt(" ; ");
} else {
if (opcode.mnemonic == S86_Mnemonic_SUB)
register_file.flags.zero = byte_op ? dest.bytes[dest_map->byte] == 0 : dest.word == 0;
S86_PrintFmt(" ; %.*s:0x%x->0x%x ", S86_STR8_FMT(dest_reg16), prev_dest16, dest.word);
S86_Str8 dest_reg16 = S86_MnemonicOpStr8(dest_map->mnemonic_op_reg16);
S86_PrintFmt(" ; %.*s:0x%x->0x%x ", S86_STR8_FMT(dest_reg16), prev_dest.word, dest.word);
*dest_map->reg = dest;
}
} break;
@ -1407,23 +1488,31 @@ int main(int argc, char **argv)
if (!S86_RegisterFileFlagsEq(register_file.flags, prev_flags)) {
S86_PrintFmt("flags:");
if (prev_flags.parity && !register_file.flags.parity)
if (prev_flags.carry)
S86_PrintFmt("C");
if (prev_flags.parity)
S86_PrintFmt("P");
if (prev_flags.zero && !register_file.flags.zero)
if (prev_flags.auxiliary_carry)
S86_PrintFmt("A");
if (prev_flags.zero)
S86_PrintFmt("Z");
if (prev_flags.sign && !register_file.flags.sign)
if (prev_flags.sign)
S86_PrintFmt("S");
if (prev_flags.overflow && !register_file.flags.overflow)
if (prev_flags.overflow)
S86_PrintFmt("O");
S86_PrintFmt("->");
if (!prev_flags.parity && register_file.flags.parity)
if (register_file.flags.carry)
S86_PrintFmt("C");
if (register_file.flags.parity)
S86_PrintFmt("P");
if (!prev_flags.zero && register_file.flags.zero)
if (register_file.flags.auxiliary_carry)
S86_PrintFmt("A");
if (register_file.flags.zero)
S86_PrintFmt("Z");
if (!prev_flags.sign && register_file.flags.sign)
if (register_file.flags.sign)
S86_PrintFmt("S");
if (!prev_flags.overflow && register_file.flags.overflow)
if (register_file.flags.overflow)
S86_PrintFmt("O");
S86_PrintFmt(" ");
}
@ -1458,8 +1547,12 @@ int main(int argc, char **argv)
S86_RegisterFileFlags nil_flags = {0};
if (!S86_RegisterFileFlagsEq(register_file.flags, nil_flags)) {
S86_PrintFmt(" flags: ");
if (register_file.flags.carry)
S86_PrintFmt("C");
if (register_file.flags.parity)
S86_PrintFmt("P");
if (register_file.flags.auxiliary_carry)
S86_PrintFmt("A");
if (register_file.flags.zero)
S86_PrintFmt("Z");
if (register_file.flags.sign)

1
part1/sim8086.h
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@ -333,6 +333,7 @@ typedef struct S86_Opcode {
S86_MnemonicOp dest; ///< Destination op for the mnemonic
int32_t displacement; ///< Opcode has displacement/data/offset
int32_t immediate; ///< Immediate value when src/dest op is an immediate
bool immediate_is_8bit; ///< Immediate was 8bit and sign extended
S86_MnemonicOp seg_reg_prefix; ///< Segment register that should prefix the upcoming instruction
} S86_Opcode;

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project.rdbg
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