// R_r(decor) applies decoration decor to register r, which is an internal
// register name. The internal register names are: `ip', `a', `b', `c', `d',
// `si', `di', `bp', `sp', `r8'--`r15'.
// R_r(decor) applies decoration decor to register r, which is an internal
// register name. The internal register names are: `ip', `a', `b', `c', `d',
// `si', `di', `bp', `sp', `r8'--`r15'.