mem: make all memory operands explicit in size

* remove non size explicit MemOp
* introduce private Mem trait
* implement Mem8, Mem16, Mem32 and Mem64 operands
* implement EncodeX helpers based on explicit memory operands
* fixup instructions with explicit memory operands
* fixup examples

2 files changed, 15 insertions, 11 deletions

diff --git a/examples/bf.rs b/examples/bf.rs
index 5d0da0b..fb75c09 100644
--- a/examples/bf.rs
+++ b/examples/bf.rs
@@ -19,7 +19,7 @@ use std::io::Write;
 
 use juicebox_asm::insn::*;
 use juicebox_asm::Runtime;
-use juicebox_asm::{Asm, Imm64, Imm8, Label, MemOp, MemOp8, Reg64, Reg8};
+use juicebox_asm::{Asm, Imm64, Imm8, Label, Mem8, Reg64, Reg8};
 
 // -- BRAINFUCK INTERPRETER ----------------------------------------------------
 
@@ -204,12 +204,14 @@ fn run_jit(prog: &str) {
                 // single add instruction during compile time.
 
                 match vm.imem[pc..].iter().take_while(|&&i| i.eq(&'+')).count() {
-                    1 => asm.inc(MemOp8::from(MemOp::IndirectBaseIndex(dmem_base, dmem_idx))),
+                    1 => {
+                        asm.inc(Mem8::indirect_base_index(dmem_base, dmem_idx));
+                    }
                     cnt if cnt <= i8::MAX as usize => {
                         // For add m64, imm8, the immediate is sign-extend and
                         // hence treated as signed.
                         asm.add(
-                            MemOp::IndirectBaseIndex(dmem_base, dmem_idx),
+                            Mem8::indirect_base_index(dmem_base, dmem_idx),
                             Imm8::from(cnt as u8),
                         );
 
@@ -225,12 +227,14 @@ fn run_jit(prog: &str) {
                 // single sub instruction during compile time.
 
                 match vm.imem[pc..].iter().take_while(|&&i| i.eq(&'-')).count() {
-                    1 => asm.dec(MemOp8::from(MemOp::IndirectBaseIndex(dmem_base, dmem_idx))),
+                    1 => {
+                        asm.dec(Mem8::indirect_base_index(dmem_base, dmem_idx));
+                    }
                     cnt if cnt <= i8::MAX as usize => {
                         // For sub m64, imm8, the immediate is sign-extend and
                         // hence treated as signed.
                         asm.sub(
-                            MemOp::IndirectBaseIndex(dmem_base, dmem_idx),
+                            Mem8::indirect_base_index(dmem_base, dmem_idx),
                             Imm8::from(cnt as u8),
                         );
 
@@ -247,7 +251,7 @@ fn run_jit(prog: &str) {
                 // then call into putchar. Since we stored all out vm state in
                 // callee saved registers we don't need to save any registers
                 // before the call.
-                asm.mov(Reg8::dil, MemOp::IndirectBaseIndex(dmem_base, dmem_idx));
+                asm.mov(Reg8::dil, Mem8::indirect_base_index(dmem_base, dmem_idx));
                 asm.mov(Reg64::rax, Imm64::from(putchar as usize));
                 asm.call(Reg64::rax);
             }
@@ -263,7 +267,7 @@ fn run_jit(prog: &str) {
                 // Goto label_pair.0 if data memory at active cell is 0.
                 //   if vm.dmem[vm.dptr] == 0 goto label_pair.0
                 asm.cmp(
-                    MemOp::IndirectBaseIndex(dmem_base, dmem_idx),
+                    Mem8::indirect_base_index(dmem_base, dmem_idx),
                     Imm8::from(0u8),
                 );
                 asm.jz(&mut label_pair.0);
@@ -280,7 +284,7 @@ fn run_jit(prog: &str) {
                 // Goto label_pair.1 if data memory at active cell is not 0.
                 //   if vm.dmem[vm.dptr] != 0 goto label_pair.1
                 asm.cmp(
-                    MemOp::IndirectBaseIndex(dmem_base, dmem_idx),
+                    Mem8::indirect_base_index(dmem_base, dmem_idx),
                     Imm8::from(0u8),
                 );
                 asm.jnz(&mut label_pair.1);
diff --git a/examples/tiny_vm.rs b/examples/tiny_vm.rs
index 1f4c653..7b40063 100644
--- a/examples/tiny_vm.rs
+++ b/examples/tiny_vm.rs
@@ -38,7 +38,7 @@
 
 use juicebox_asm::insn::*;
 use juicebox_asm::Runtime;
-use juicebox_asm::{Asm, Imm16, Imm64, MemOp, Reg16, Reg64};
+use juicebox_asm::{Asm, Imm16, Imm64, Mem16, Reg16, Reg64};
 
 /// A guest physical address.
 pub struct PhysAddr(pub u16);
@@ -285,11 +285,11 @@ impl TinyVm {
 
             // Generate memory operand into regs for guest register.
             let reg_op = |r: TinyReg| {
-                MemOp::IndirectDisp(Reg64::rdi, (r.idx() * 2).try_into().expect("only 3 regs"))
+                Mem16::indirect_disp(Reg64::rdi, (r.idx() * 2).try_into().expect("only 3 regs"))
             };
 
             // Generate memory operand into dmem for guest phys address.
-            let mem_op = |paddr: u16| MemOp::IndirectDisp(Reg64::rsi, paddr.into());
+            let mem_op = |paddr: u16| Mem16::indirect_disp(Reg64::rsi, paddr.into());
 
             // Compute instructions in translated basic block.
             let bb_icnt = || -> u64 { (pc - self.pc).try_into().unwrap() };