24531904_j

操作 : if (PR[qp]) {
check_target_register(r 1);
if (one_byte_form) { // one-byte elements
x[0] = GR[r 2]{7:0}; y[0] = GR[r 3]{7:0};
x[1] = GR[r 2 ]{15:8}; y[1] = GR[r 3 ]{15:8};
x[2] = GR[r 2 ]{23:16}; y[2] = GR[r 3 ]{23:16};
x[3] = GR[r 2 ]{31:24}; y[3] = GR[r 3 ]{31:24};
x[4] = GR[r 2 ]{39:32}; y[4] = GR[r 3 ]{39:32};
x[5] = GR[r 2 ]{47:40}; y[5] = GR[r 3 ]{47:40};
x[6] = GR[r 2 ]{55:48}; y[6] = GR[r 3 ]{55:48};
x[7] = GR[r 2 ]{63:56}; y[7] = GR[r 3 ]{63:56};
if (sss_saturation_form) {
max = sign_ext(0x7f, 8);
min = sign_ext(0x80, 8);
for (i = 0; i < 8; i++) {
temp[i] = sign_ext(x[i], 8) + sign_ext(y[i], 8);
}
} else if (uus_saturation_form) {
max = 0xff;
min = 0x00;
for (i = 0; i < 8; i++) {
temp[i] = zero_ext(x[i], 8) + sign_ext(y[i], 8);
}
} else if (uuu_saturation_form) {
max = 0xff;
min = 0x00;
for (i = 0; i < 8; i++) {
temp[i] = zero_ext(x[i], 8) + zero_ext(y[i], 8);
}
} else { // modulo_form
for (i = 0; i < 8; i++) {
temp[i] = zero_ext(x[i], 8) + zero_ext(y[i], 8);
}
}
if (sss_saturation_form || uus_saturation_form ||
uuu_saturation_form) {
for (i = 0; i < 8; i++) {
if (temp[i] > max)
temp[i] = max;
}
if (temp[i] < min)
temp[i] = min;
}
GR[r 1 ] = concatenate8(temp[7], temp[6], temp[5], temp[4],
temp[3], temp[2], temp[1], temp[0]);
} else if (two_byte_form) { // 2-byte elements
x[0] = GR[r 2]{15:0}; y[0] = GR[r 3]{15:0};
x[1] = GR[r 2 ]{31:16}; y[1] = GR[r 3 ]{31:16};
x[2] = GR[r 2 ]{47:32}; y[2] = GR[r 3 ]{47:32};
x[3] = GR[r 2]{63:48}; y[3] = GR[r 3]{63:48};
if (sss_saturation_form) {
max = sign_ext(0x7fff, 16);
min = sign_ext(0x8000, 16);
3:178 第 3 巻 : 命令リファレンス
padd