tcg: Document ctpop opcodes

Fixes: a768e4e99247
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/658
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/tcg/README b/tcg/README
index c2e7762..bc15cc3 100644 (file)
--- a/tcg/README
+++ b/tcg/README
@@ -254,6 +254,12 @@ t0 = t1 ? clz(t1) : t2
 
 t0 = t1 ? ctz(t1) : t2
 
+* ctpop_i32/i64 t0, t1
+
+t0 = number of bits set in t1
+With "ctpop" short for "count population", matching
+the function name used in include/qemu/host-utils.h.
+
 ********* Shifts/Rotates
 
 * shl_i32/i64 t0, t1, t2