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x86_64: refactor immediate selection logic

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This commit is contained in:
Jakub Konka 2023-03-08 09:49:59 +01:00
parent 219c1261a5
commit 5b37701028
2 changed files with 29 additions and 34 deletions
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59
src/arch/x86_64/Encoding.zig
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@ -453,7 +453,8 @@ pub const Op = enum {
pub fn bitSize(op: Op) u64 {
return switch (op) {
.none, .o16, .o32, .o64, .moffs, .m, .sreg => unreachable,
.unity, .imm8, .imm8s, .al, .cl, .r8, .m8, .rm8, .rel8 => 8,
.unity => 1,
.imm8, .imm8s, .al, .cl, .r8, .m8, .rm8, .rel8 => 8,
.imm16, .imm16s, .ax, .r16, .m16, .rm16, .rel16 => 16,
.imm32, .imm32s, .eax, .r32, .m32, .rm32, .rel32, .xmm_m32 => 32,
.imm64, .rax, .r64, .m64, .rm64, .xmm_m64 => 64,
@ -462,6 +463,18 @@ pub const Op = enum {
};
}
pub fn isSigned(op: Op) bool {
return switch (op) {
.unity, .imm8, .imm16, .imm32, .imm64 => false,
.imm8s, .imm16s, .imm32s => true,
else => unreachable,
};
}
pub fn isUnsigned(op: Op) bool {
return !op.isSigned();
}
pub fn isRegister(op: Op) bool {
// zig fmt: off
return switch (op) {
@ -516,8 +529,7 @@ pub const Op = enum {
};
}
/// Given an operand `op` checks if `target` is a subset for the purposes
/// of the encoding.
/// Given an operand `op` checks if `target` is a subset for the purposes of the encoding.
pub fn isSubset(op: Op, target: Op, mode: Mode) bool {
switch (op) {
.m, .o16, .o32, .o64 => unreachable,
@ -544,36 +556,19 @@ pub const Op = enum {
}
if (op.isImmediate() and target.isImmediate()) {
switch (target) {
.imm64 => switch (op) {
.unity, .imm8s, .imm8, .imm16s, .imm16, .imm32s, .imm32, .imm64 => return true,
else => return op == target,
},
.imm32s, .rel32 => switch (op) {
.unity, .imm8s, .imm8, .imm16s, .imm16, .imm32s => return true,
else => return op == target,
},
.imm32 => switch (op) {
.unity, .imm8, .imm8s, .imm16, .imm16s, .imm32, .imm32s => return true,
else => return op == target,
},
.imm16s, .rel16 => switch (op) {
.unity, .imm8s, .imm8, .imm16s => return true,
else => return op == target,
},
.imm16 => switch (op) {
.unity, .imm8, .imm8s, .imm16, .imm16s => return true,
else => return op == target,
},
.imm8s, .rel8 => switch (op) {
.unity, .imm8s => return true,
else => return op == target,
},
.imm8 => switch (op) {
.unity, .imm8, .imm8s => return true,
else => return op == target,
},
else => return op == target,
.imm64 => if (op.bitSize() <= 64) return true,
.imm32s, .rel32 => if (op.bitSize() < 32 or (op.bitSize() == 32 and op.isSigned()))
return true,
.imm32 => if (op.bitSize() <= 32) return true,
.imm16s, .rel16 => if (op.bitSize() < 16 or (op.bitSize() == 16 and op.isSigned()))
return true,
.imm16 => if (op.bitSize() <= 16) return true,
.imm8s, .rel8 => if (op.bitSize() < 8 or (op.bitSize() == 8 and op.isSigned()))
return true,
.imm8 => if (op.bitSize() <= 8) return true,
else => {},
}
return op == target;
}
return false;
},

4
src/arch/x86_64/bits.zig
View File

@ -525,13 +525,13 @@ pub const Immediate = union(enum) {
pub fn asUnsigned(imm: Immediate, bit_size: u64) u64 {
return switch (imm) {
.signed => |x| switch (bit_size) {
8 => @bitCast(u8, @intCast(i8, x)),
1, 8 => @bitCast(u8, @intCast(i8, x)),
16 => @bitCast(u16, @intCast(i16, x)),
32 => @bitCast(u32, @intCast(i32, x)),
else => unreachable,
},
.unsigned => |x| switch (bit_size) {
8 => @intCast(u8, x),
1, 8 => @intCast(u8, x),
16 => @intCast(u16, x),
32 => @intCast(u32, x),
64 => x,