py/asmx64: Support use of top 8 regs in src_r64 argument.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

py/asmx64.c

@@ -285,31 +285,28 @@ void asm_x64_mov_r64_to_mem64(asm_x64_t *as, int src_r64, int dest_r64, int dest
 }
 
 void asm_x64_mov_mem8_to_r64zx(asm_x64_t *as, int src_r64, int src_disp, int dest_r64) {
- assert(src_r64 < 8);
- if (dest_r64 < 8) {
+ if (src_r64 < 8 && dest_r64 < 8) {
  asm_x64_write_byte_2(as, 0x0f, OPCODE_MOVZX_RM8_TO_R64);
  } else {
- asm_x64_write_byte_3(as, REX_PREFIX | REX_R, 0x0f, OPCODE_MOVZX_RM8_TO_R64);
+ asm_x64_write_byte_3(as, REX_PREFIX | REX_R_FROM_R64(dest_r64) | REX_B_FROM_R64(src_r64), 0x0f, OPCODE_MOVZX_RM8_TO_R64);
  }
  asm_x64_write_r64_disp(as, dest_r64, src_r64, src_disp);
 }
 
 void asm_x64_mov_mem16_to_r64zx(asm_x64_t *as, int src_r64, int src_disp, int dest_r64) {
- assert(src_r64 < 8);
- if (dest_r64 < 8) {
+ if (src_r64 < 8 && dest_r64 < 8) {
  asm_x64_write_byte_2(as, 0x0f, OPCODE_MOVZX_RM16_TO_R64);
  } else {
- asm_x64_write_byte_3(as, REX_PREFIX | REX_R, 0x0f, OPCODE_MOVZX_RM16_TO_R64);
+ asm_x64_write_byte_3(as, REX_PREFIX | REX_R_FROM_R64(dest_r64) | REX_B_FROM_R64(src_r64), 0x0f, OPCODE_MOVZX_RM16_TO_R64);
  }
  asm_x64_write_r64_disp(as, dest_r64, src_r64, src_disp);
 }
 
 void asm_x64_mov_mem32_to_r64zx(asm_x64_t *as, int src_r64, int src_disp, int dest_r64) {
- assert(src_r64 < 8);
- if (dest_r64 < 8) {
+ if (src_r64 < 8 && dest_r64 < 8) {
  asm_x64_write_byte_1(as, OPCODE_MOV_RM64_TO_R64);
  } else {
- asm_x64_write_byte_2(as, REX_PREFIX | REX_R, OPCODE_MOV_RM64_TO_R64);
+ asm_x64_write_byte_2(as, REX_PREFIX | REX_R_FROM_R64(dest_r64) | REX_B_FROM_R64(src_r64), OPCODE_MOV_RM64_TO_R64);
  }
  asm_x64_write_r64_disp(as, dest_r64, src_r64, src_disp);
 }